Check the listing for details. 12V DC dimmer, 12V rotary dimmer switch for RV Boat LED lighting. Condition: New. Listed at 15.49 USD. Product Features Be Applicable---For LED lighting, incandescent, halogen or anywhere 12 volt DC power is present. Perfect for rvs, trailers, boats, cars, and trucks. Safety Devices---Built-in resistors, no need to connect additional resistors, avoid loop to protect the equipment.Added heat dissipation area on the back effective reduce heat and raise energy efficiency. Easy to Operate---Rotate button, brightness can be adjusted according to demand, audible clicking sound when closing. Quick Connection and Usage---Clear 3-wires Configuration, Red wires to input and output positive, Black wires to input negative, Blue wires to output negative. Support Custom Panel Mount---The black knob on the front of the dimmer can be removed and directly pulled out, rather than rotated.