The Bisun R3 unit is a mid-range light, more flexible than the S3, but simpler in operation than the P51.
It is a replacement for the previous M2/M3 and X3 models.
Independent electronics are used for each LED for maximum reliability, and each beam has three power levels, of around 20, 60, and 150 lumens.
An R3 can be configured to share some power between the LEDs (gently, so the flood LED can have a little spot beam to extend its range, or more strongly, to give a more equal mix), or for the beams to be pure flood and spot beams.
Operating at the high (150 lumen) setting, the M3/X3 consumes about 370mA, much less than most halogen bulbs.
For comparison, a 3.6V/0.85A halogen bulb produces something like 40 lumens.
The Bisun R3 units work in FX3s, lead-acid powered Oldham lamps, Headlite
headlamps using any Headlite battery, and other commercial or home-made systems with 3.6-4.5V power using regular Oldham or CEAG (Speleotechnics) headsets.