Powerdecal Light Up Car Decal POWERDECAL is an LED backlit logo for your vehicle window. Device turns on automatically while driving at night via sensor technology. Device shuts off after 2 minutes once parked. Easy installation with quality 3M adhesion material. Just peel and stick, no tools required. Batteries and window clips are included. 4 Inch in diameter. POWERDECAL is an LED backlit logo for your vehicle window. Device turns on automatically while driving at night via sensor technology. Device shuts off after 2 minutes once parked. Easy installation with quality 3M adhesion material. Just peel and stick, no tools required. Batteries and window clips are included. 4" in diameter.