T8 tombstone recessed double contact R17D. The socket is non shunted socket. CE and Rohs listed. Great socket to retrofit existing fixtures. Use to update the T8 fixture to use R17D tubes versus C13 or single pin tubes. Each socket is shunted meaning 1 wire for both terminals on each T8 socket. Sold 1 matched per package (1 stationary, 1 plunger). cUL, 600W 600V