The DENALI HI-LOW-OFF Switch replaces the standard ON-OFF switch. The switch enables independent dimming of the lights, separate from the vehicle's OEM lighting system. This eradicates the issues presented by vehicles that do not provide and a clean 12v high beam trigger signal. This switch is also a great option for those who want full independent control of their auxiliary lights. In addition to molded silicone gasket seals, we use a unique DrySeal™ construction technique that encases the wires in a potted cavity as they enter the housing. This ensures our housings are 100% watertight even when submerged underwater with the wires cut and connector removed. Note: Requires the DataDim™ Dual-Intensity Controller What’s In The Box? (x1) DrySeal™ HI-LOW-OFF Waterproof Switch (x1) Adhesive Pad Instruction Manual