Use this adapter to utilize G4 Bi-Pin based bulbs in your 1156/1141 Single Contact BA15S sockets. Works especially well for our disc LEDs in many RV and Camper lighting applications and for the reading lamps when used in conjunction with our MR11 & MR16 G4 LED light bulbs. Not designed for automotive tail lights usage. Standard 15mm socket diameter. Suitable for the Gu5.3 and G4 type bi-pin lampsAlso, for outside landscape lighting and heat resistant with ceramic insulators for Halogen as well. There's a 10 lot here in this sale. Warranty by Wired Communications.