The M91B is the newest addition to the Malkoff Devices line of LED drop-in modules. Like its predecessor, the M91A, the new M91B is designed for use with the Malkoff line of full-size flashlight bodies or as a direct drop-in replacement for the SureFire P90 incandescent lamp assembly used by the SureFire 9P, C3 Centurion, and Z3 CombatLight.
Suitable for handheld and weapon mounted applications, the new M91B is outfitted with a cool white Cree XP-L emitter rated to produce approximately 825 lumens at turn on and 700 lumens during continuous operation. When used in conjunction with a Malkoff flashlight body and high/low bezel ring a 30 to 40 lumen (approximately) low mode is also available. The M91B has a retail price of $89.00.
Malkoff M91B – Overview
At first glance the new M91B looks like any other Malkoff drop-in with its distinctive design and solid brass heatsink. However a look inside the custom orange peel reflector reveals the Cree XP-L emitter, a first for Malkoff Devices.
The brass heatsink is sized to fit perfectly in Malkoff or SureFire hosts without the use of an outer spring. A small center spring is used to maintain electrical contact with the battery and all electronics are fully potted for durability.
When installed in a Malkoff bezel the M91B may be used with the MD2, MD3 or MD4 flashlight bodies permitting a wide variety of battery configurations.
Installation in a SureFire host is as simple as removing the bezel and replacing the stock lamp assembly with the M91B.
Malkoff M91B – Performance
The large XP-L emitter and relatively small reflector produce what could be characterized as a floody beam that still has good reach. The broad center hotspot has a slightly off-white tint and is surrounded by a very large corona which tapers off into the remainder of the spill beam. The outermost portion of the spill is noticeably cool but the corona has a slight yellow tint which gives the overall beam a warmer appearance. There are some rings present in the beam but they are most obvious when illuminating nearby objects (white wall hunting) and were not an issue in normal use.
When compared to the previous M91A, the M91B provides a boost in both total output and beam reach, with its broad hotspot providing good illumination out to 60-80 yards. The following slides compare the Malkoff M91B to a variety of other lights to provide perspective with regard to output, beam profile, and beam tint. The beamshots can be compared across the full width of the image using the slider and additional comparisons may be accessed using the navigation buttons in the bottom-right corner of each image.
The following lights are shown for comparison:
- Malkoff MD2 with M61 drop-in (Review)
- SureFire P2X Fury (Review)
- Elzetta Bravo AVS (Review)
- Malkoff MD2 with M91 drop-in
- Malkoff MD3 with M91A drop-in
- FourSevens Maelstrom Regen MMR-X (Review)
- Elzetta Charlie AVS (Review)
- Malkoff Hound Dog V3 (Review)
- Malkoff Wildcat V4 (Review)
- Malkoff Wildcat V5 (Review)
Beamshots – 30 Yards to Swing
Beamshots – 40 Yards to Swing
With its wide operating voltage range, the M91B can be powered by two lithium-ion rechargeable batteries or from 2 to 4 CR123 lithium primary batteries. Malkoff MD2, MD3 and MD4 bodies were used to conduct runtime testing with several of the most frequently used battery types.
The CR123 lithium primary batteries used in these tests were provided by Battery Station. Their support has been invaluable.
Due to the large number of tests, the results are separated into two charts, one for rechargeable lithium-ion batteries and other for CR123 lithium primary batteries.
The output level was extremely consistent between the various types of rechargeable batteries used during the test and all battery types maintained very stable regulation. Protected batteries (AW 18650 3400mAh, AW 18500 1500mAh, and AW 16340 750mAh) all ran until their overdischarge protection circuit was activated causing the light to shut off completely. During tests with the IMR batteries, the light began to blink on and off when the operating voltage dropped too low.
Output and regulation were also very stable when the M91B was powered by either 3 or 4 CR123 cells (2 x AW 18650 3400mAh from previous chart shown as a baseline). The drop-in is not intended for use with only two CR123 batteries but testing verifies that this would be possible in an emergency, although output and runtime would be less than the other configurations.
When operated continuously, the light became very warm but not quite too hot to hold.
Malkoff M91B – Conclusions
The Malkoff M91B is a very powerful drop-in and is also extremely versatile due to its broad support for a number of different battery options. It is well suited for use in hosts such as a stock SureFire 9P although larger hosts that can accommodate 18mm batteries, such as the Malkoff MD4 body, are necessary to achieve maximum performance. Output is consistent across the different battery configurations and regulation is rock solid. Construction is top notch and I can’t think of any type of usage that would be more than the drop-in couldn’t handle.
I consider the beam produced by the M91B to be more useful than its predecessor, the M91A. It’s not so much a matter of sheer output but rather the slight increase in throw makes a noticeable difference when used outdoors. Also, in contrast to the very cool white of my M91A the warmer tone of the M91B is easier on the eyes. Those in search of the “perfect beam” likely won’t be satisfied by the coloration and rings present in the M91B but these have proven to be non-issues in my use so far.
As always when purchasing from Malkoff Devices, the order was shipped promptly, arrived safely, and included a handwritten note of appreciation. This is one company that is always a pleasure to do business with.
Visit the Malkoff Devices website for more information about the M91B drop-in.