All Tek-Lights, New Wave® 42, 44, 48 have program start ballasts. New Wave® 22, 24, 28 and Sun Blaze® 22, 24, 44, 48 have instant start ballasts. Excellent quality, reliable socket. UL listed component. Rotate lamp 90 degrees to lock in place. Program start ballasts require non-shunted sockets. Instant start ballasts require shunted sockets.