Size: 12mm*36mm, this bulb is larger than a traditional halogen bulb. Non-dimmable, please don't use them with dimmer or unstable 12 volts, or the bulbs will flicker or make noise Standard g4 bi pin base, can be easily fitted instead of ordinary halogen bulbs. AC/DC 12V G4 LED light bulbs are used for landscape lighting, RV,courtyard, garden, puck lights, under cabinet lighting, post lights, recessed light and etc. Replace 20W halogen bulb by 3W LED, save 85% on Energy of lighting. If you use this bulb to replace the halogen lamp and the bulb are flickering after installtion; there are two way to aviod flickering: 1. Change your transformer to LED driver; 2. Keep one halogen lamp in your light system, don't all install led G4 LED Bulb 12V Bi Pin Base Replace 20W Halogen Bulbs for Home and Landscape Lighting Non-dimmable, 3W Warm White 2700K, 5 Pcs