Its the Surefire KL4 bezel thats been modified by CPF supremo McGizmo. The stock 5 watt luxeon has been taken out and replaced with either a 1 watt or 3 watt Luxeon. These produe less overall light output, but make a far more intense spot, making it a better light than the stock KL4 for those times when you need to put a point of light on a distant object.