Brinyte PT28 Oathkeeper Flashlight Review

Here’s the Brinyte PT28 Oathkeeper Flashlight, and it’s well-featured. It offers magnetic charging and a tactical ring. Read on for more!

Official Specs and Features

Here’s a link to the Brinyte PT28 Oathkeeper Flashlight product page.

Versions

I think there’s just one emitter option but there are two body colors. Desert tan (seen here) and black.

Price

These go for $122 on Brinyte’s store.

Short Review

This is a nice light. It’s very capable and meets specifications. The emitter is very cool white (angry white, even), so that’s not my favorite feature.

Long Review

The Big Table

Brinyte PT28 Oathkeeper Flashlight
Emitter:	Cree XHP35 HD
Price in USD at publication time:	$122.00
Cell:	1×18650
Turbo Runtime	High Runtime
LVP?	Yes
Switch Type:	Dual
On-Board Charging?	Yes
Chargetime
Power off Charge Port with no Cell?	One mode. With cell: two modes.
Claimed Lumens (lm)	1600
Measured Lumens (at 30s)	1716 (107.3% of claim)^
Candela per Lumen	7.6
Claimed Throw (m)	?
Candela (Calculated) in cd (at 30s)	630lux @ 5.301m = 17703cd
Throw (Calculated) (m)	266.1^
All my Brynite reviews!

^ Measurement disclaimer: Testing flashlights is my hobby. I use hobbyist-level equipment for testing, including some I made myself. Try not to get buried in the details of manufacturer specifications versus measurements recorded here; A certain amount of difference (say, 10 or 15%) is perfectly reasonable.

What’s Included

Brinyte PT28 Oathkeeper flashlight
Brinyte 3400mAh 18650
Charge cable (USB to proprietary magnetic)
Nylon belt pouch (with 18650 holder)
Tactical tailcap cover finger ring
Paracord lanyard with metal clip

Package and Manual

I didn’t get a manual with this light, unfortunately. I’d love to have one. I imagine your purchase will come with a manual.

Build Quality and Disassembly

Build quality is good. The light feels good in my hands.

A bronze-colored flashlight with a circular ring attachment stands upright on a weathered wooden surface, with a blurred outdoor background.

A metallic flashlight with a side clip stands upright on a weathered wooden surface, with a blurred outdoor background. The flashlight features a button and grooved grip on its lower section.

A bronze-colored tactical flashlight with a circular ring attachment stands upright on a wooden surface, shown in focus with a blurred wooden background.

A metallic flashlight with a clip stands upright on a wooden surface outdoors. The background is blurred, and the product has ridges and a button on its body.

The tactical ring adds a bit of bulk on the tailcap but that’s expected.

It’s also keyed, so it’ll only go on in one spot, and it won’t spin around when it’s installed. There’s a little bit of play when installed, but not much.

The threads are unanodized and square-cut. The onboard charging necessitates the inner sleeve, which can be seen peeking out below.

As you’d expect, both head and tail end have springs. A tactical light needs that.

The body design is well planned enough that the little divot the tac ring is keyed to is very subtle.

The bezel also has some relief to allow light to show when headstanding.

Size and Comps

There aren’t any official size specs. All these measurements are my own.

Light (with clip, without cell, without tac ring): 108g
Tac ring: 18g
Included 18650: 48g

A metallic flashlight is placed next to a two-dollar bill on a weathered wooden surface, showing a size comparison between the flashlight and the banknote.

A close-up, top-down view of a metal object with a black circular end, placed vertically on a wooden surface, with a blurred US dollar bill underneath.

A person holding a metallic flashlight with a ring on the end, outdoors with grass in the background. The flashlight is gripped firmly in the right hand.

A left hand holds a metallic flashlight with a visible side switch and a knurled grip, against a grassy outdoor background. The flashlight features a trigger-like attachment near the thumb.

A hand holding a bronze-colored flashlight horizontally outdoors, with grass visible in the background. The flashlight has a textured grip and visible branding on the side.

Pretty long light here.

Two flashlights stand upright on a weathered wooden surface outdoors. The flashlight on the left is shorter and red, while the one on the right is taller, metallic, and bronze-colored. The background is blurred.

Two flashlight heads lying on their sides on a wooden surface, one with four yellow LED emitters and the other with a single yellow LED emitter, both out of focus in the background.

Retention and Carry

I’m not sure what the “most preferred” way to carry the PT28 will be. The nylon pouch is quite … featured. There’s a rotating plastic belt loop and a stretchy 18650 holder.

A black nylon case with a flap labeled BRINYTE sits vertically against weathered wooden boards. The stitching and texture of the case are visible.

A black nylon pouch with a hook-and-loop strap and a metal belt clip holds a cylindrical object, photographed from above on a weathered wooden surface.

A black Brinyte-branded fabric flashlight holster with a blue flashlight partially visible on the right side, placed vertically on weathered wooden planks.

A black nylon case with a vertical strap and belt clip is holding a cylindrical object, placed on a weathered wooden surface.

It’s a good pouch. I don’t really use pouches, but this one is nice.

A black nylon pouch with a large metal clip attached, placed vertically on weathered wooden boards. A blue edge and some webbing detail are visible on the left side of the pouch.

A black nylon holster with a metal belt clip is placed on a weathered wooden surface. The holster appears to be closed and has a visible elastic band on the side. The text ZEROAIR.ORG is visible on the left.

A black nylon pouch with a metal belt clip attached, positioned vertically on a weathered wooden surface. The pouch has visible stitching, snaps, and a blue accent on the side.

A black nylon pouch with a metal clip is secured to weathered wooden planks. The fabric has visible stitching and two metal rivets on the clip. Part of a blue object is partially visible inside the pouch.

The head and tail are exposed for use while in the pouch, too. Also note the 18650 which is installed in the pouch below.

A hand holding a black fabric pouch with a circular silver and black button on top, resting on weathered wooden planks. A small blue object is partially visible attached to the pouch.

A hand holds a small black flashlight headlamp with a yellow LED at the center, a blue button on the side, and a Velcro strap, against a weathered wooden background.

The light also fits with the tactical ring installed.

Also included is a lanyard, which has the features of a normal good lanyard and has a metal clip for very easy attachment.

This clip is likely intended to fit on the tailcap loops (either of 2) but it’ll also fit in two places on the pocket clip.

A close-up, top-down view of a metallic device attached to a green and brown braided lanyard, resting on weathered wooden boards. The device has a round black button or dial in the center.

A compact flashlight with a camouflage-patterned wrist strap and a metal ring is placed on a weathered wooden surface.

A metallic flashlight with a paracord lanyard attached is resting on weathered wooden boards. The flashlight has a ring near the end and engraved text on the side.

Another way to handle the light is this tactical ring. As I said above, it’s keyed, and so won’t rotate when installed, but also has just about 2mm worth of play when installed.

The tac ring doesn’t prevent any other retention option. Finally, below, see the pocket clip. It’s a friction fit clip and very snug. Not a cheap clip either – it has smooth edges.

A close-up of a metallic flashlight with a side clip, labeled “T28 Oathkeeper,” lying on a wooden surface with a blurred background.

A close-up of a metallic flashlight lying on a wooden surface, showing its side clip, textured grip, and rear end with a lanyard hole. The background is blurred.

Power and Runtime

The PT28 is powered by a single 18650. Brinyte includes a cell suitable for this light. It’s also possible to run this light on 2x CR123 because the acceptable top voltage is 6V.

A close-up view of a single blue AA battery lying on its side on a weathered wooden surface. The positive terminal faces the camera, and the batterys label is partially visible.

A close-up of a blue cylindrical battery lying on its side on a weathered wooden surface, with the focus on the terminal end of the battery.

The cell goes in with the positive end toward the head (as with most lights).

Here are two runtime tests. Turbo and high.

I wasn’t able to test the light with my bench power (something just didn’t work right) but the runtimes do indicate clearly that the light has LVP at around 3V. High output is exceptionally stable for nearly the entire runtime.

Charging

The included charge cable is USB to proprietary magnetic. That connector connects to the head port seen below.

Charging proceeds at around 2A, which is a good charge rate. Full charging takes only around 2 hours.

During charge, the indicating switch is red. When the charge is complete, the switch turns green. If something is wrong, the switch is orange. All during this time, the magnetic charge connector is blue (bright blue).

Modes and Currents

Mode	Mode Claimed Output (lm)	Claimed Runtime	Measured Lumens	Tailcap Amps
Turbo	1600	1m+109m	1716	?
High	360	210m	388	?
Medium	60	960m	60	0.09
Low	10	5880m	12	0.02

Pulse Width Modulation

There’s a bit of ripple on low (left) but no PWM anywhere to be seen.

An oscilloscope screen displays a yellow waveform with regular peaks and troughs. The settings at the bottom read 1V DC, 50µs, AUTO, Int, -0.12V. Status indicators show Running and Waiting.

Digital oscilloscope screen shows a mostly flat yellow waveform near the center. The settings indicate 2V/div, 50 microseconds/div, DC coupling, and AUTO trigger mode. The status bar reads Waiting.

Oscilloscope screen showing a nearly flat yellow trace near the top, grid lines, and status indicators: HOLD, Waiting, voltage at 2V/div, timebase at 50μs/div, DC coupled, and baseline at -0.24V.

A digital oscilloscope display shows a mostly flat yellow waveform line near the top of the grid. The screen reads HOLD in red and Waiting in green. Settings: 2V, DC, 50µs, AUTO, and -0.24V.

Here you can see a “baseline” – a chart with almost no light hitting the sensor.

Then there’s the Ultrafire WF-602C flashlight, which has some of the worst PWM I’ve seen. It’s so bad that I used a post about it to explain PWM! Here are multiple timescales (10ms, 5ms, 2ms, 1ms, 0.5ms, 0.2ms) to make comparing this “worst” PWM light to the test light easier. That post also explains why I didn’t test the WF-602C at the usual 50us scale.

User Interface and Operation

There are two switches on the PT28. First is the mechanical tail switch. It has a nice Brinyte logo.

Secondly is the e-switch on the head, which is exactly opposite to the charge port. This is an indicating switch. Right after turning the light on, the switch will indicate the charge level, as follows:

Green: ≥70%
Orange: 30-70%
Red Steady: <30%
Red Flashing: <10%

I didn’t get a manual so I could very well miss something in the UI.

Here’s a user interface table!

State	Action	Result
Off	Click Tail Switch (TS)	On (last used mode)
Off	Click Side Switch (SS)	No action
On	Click TS	Off
On	Click SS	Mode advance (LMHT)
On	Hold SS	No action
On	Double click SS	Strobe
Off	Tap TS	Momentary (Last used)^
Off	Double-tap TS	Momentary Strobe

^ It is not possible to change the mode while in momentary output.

LED and Beam

The emitter is a Cree XHP35 HD, and quite cool white. I suppose I’d guess it at around 6500K but it could be cooler. You sort of expect that out of a tactical light, I think, but it can still be a shade jarring. The reflector is smooth.

These beamshots always have the following settings: f8, ISO100, 0.3s shutter, and manual 5000K exposure. These photos are taken at floor level, and the beam hits the ceiling around 9 feet away.

A dim, circular blue light appears in the center of a mostly black background. The text ZEROAIR.ORG is vertically aligned along the left edge.

A circular white light is centered against a dark background, creating a bright spot with a gradient halo effect. The text “ZEROAIR.ORG” appears vertically on the left side of the image.

A bright white circular light beam is projected onto a dark background, creating a gradient effect from the center outward. The text ZEROAIR.ORG appears vertically along the left side of the image.

A bright, circular beam of white light is projected onto a dark surface. The light fades gradually towards the edges. The text ZEROAIR.ORG is vertically visible on the left side of the image.

Tint vs BLF-348 (KillzoneFlashlights.com 219b version) (affiliate link)

I keep the test flashlight on the left and the BLF-348 reference flashlight on the right.

I compare everything to the Killzone 219b BLF-348 because it’s inexpensive and has the best tint!

Random Comparisons and Competitive Options

Here’s a link to a relevantly filtered page on parametrek.com. I use that site a lot!

Conclusion

What I like

Good build quality
Complete package
Does not require a proprietary cell for built-in charging
Nice pouch included

What I don’t like

Proprietary charge connection
Very CW emitter temperature

Notes

This light was provided by Brinyte for review. I was not paid to write this review.
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