It is powered by built in batteries with ultra low power consumption. The batteries can be used for about one year to two years. It is applicable to most of the DVD navigation with direction control function on the market.This controller is universal, so you 't need to remove the steering wheel controller to work. It can support 5 buttons and 10 buttons two choices to meet the common operation needs of the car. super Touch-design, small space occupation and side button will not cause the wrong operation by steering the wheel.Integrated arc design is perfectly compatible with a of car steering wheels, without bad effect to the steering wheel cover.Being flexibly installed along the steering wheel as you like, this controller is easy to use and helpful to keep safety for your driving.Item Type: Remote Controls Features: Easy installation and removal.Item Weight: 0.18kgModel Name: Controller KeyProduct name: Steering Wheel remote controlShape: Half MoonController Key Size (LxWxH ): about 10 x 4.4 x 3.5 cm/3.9inch x 1.7inch x 1.4inchReceiver Box Size (LxWxH ): about 4.3 x 3.7 x 1 cm/1.7inch x 1.45inch x 0.45inchMaterial:ABScolour:BlackPackage Contents:2 x Controller Key (with built-in button battery)1 x Receiver Box1 x Wire harness1 Set x Screws1 x Instruction manualOnly the above package content, other are not included.Note: Light and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed is +/- 1-3cm.