All automobiles and motorcycles use 12V DC power. DC stands for Direct Current. This is different than the LED Car Bulbs power in your homes outlets. Homes use 120V AC, which stands for alternating current. You cannot connect one to the other, as it would cause damage and danger.
Normal little leds you can purchase from the internet or the store run at much less voltage than 12V, usually 2-4V. Thus, for this reason you must attach special valued resistors to these leds to use in your car. We take this this guess work and trouble of sitting there soldering resistors to these leds away. Its plug and play to all 12V DC applications. Incase you want to use in your home, all you need is an AC-DC adaptor. These can be purchased from the internet and local stores. They are usually used to replace damaged AC-DC adaptors of portable electronics.