Adjustable Keyless Candle Sockets are Edison base E26 often referred to as medium or standard base. They are a changeable type enabling height to be adjusted from 4" to 5-1/2". Once installed and covered with a candle sleeve they offer the appearance of electric candles to antique lamps, wall sconces and chandeliers. When wiring, use included cardboard insulator to cover socket terminals. Cover socket and insulator with candle sleeve. Use with standard, Edison bulbs.