Like it's predecessor, THE HEAD, the RHEOHEAD features a brightness intensity knob that can brighten and dim your bulb to provide more versatility and battery conservation. It comes standard on the Nite Sport II, or can be purchased separately to convert you older style Nite packages. It is also compatible with the Coon Hunters Favorite II and Kitten Kooner II.The most popular headlamp on the market today! Features include:Adjustable beamBrilliant blue-white spotHeavier molded cordRugged ABS housingSpare bulb holderPre-spotted bulbMetal cap hookRugged and lightweightThe highly polished reflector throws a brilliant blue-white spot using a pre-spotted bulb to assure the power beam pattern every time. The light can be easily flared out to a wide walking light. The RHEOHEAD features a moisture-proof O-ring seal around the lens, a neoprene seal around the lens as well as a weatherproof switch. A plastic shield covers all working parts of the head and provides a spare bulb holder inside the headpiece. The unusual clip design allows easy attachment to a soft cap, hardhat, battery or a rifle barrel with the new barrel clip. THE HEAD may be used with either 4, 6, or 12 volt systems.