Bisun design and make a range of twin-beam LED light units, with designs evolving since 2004 to keep up with user demands and the latest LED technology.

All units share the same optical arrangement to give great beamshapes that make particularly efficient use of the light from each LED, and maximise usability at all power levels, for both the spot and flood LEDs.
All units fit into Oldham and CEAG (Speleotechnics) mining lamp headsets, and the P51m is also available built into a complete headset/battery box setup.

The main units in the current line-up are the top-of-the-range P51m, with independent multilevel power control for each LED and flexible beam blending, the simpler but still flexible R3 unit, and the non-configurable fixed-power S3.
All those units run off 3.6-4.5V power, and so are usable in a variety of existing Oldham and CEAG headsset-based systems (FX3s, Headlites, etc), although the P51 is not compatible with Oldham lamps running on lead-acid batteries.

For 2.4V systems (FX2/DX2, or similar) the X2 insert is a fantastic upgrade. Each LED operates at the same fixed power output, giving better runtime and far more light output than using old-fashioned bulbs, as well as the choice of the two great beamshapes.