Master set includes a wide array of bits: metric hex, SAE hex, Phillips, Phillips ACR, slotted, triple square (XZN), TORX, TORX Plus, TORX tamper resistant, TORX Plus tamper resistant, MORTORQ, square (Robertson) and clutch. Bits are made of S2 steel. Features super low profile sockets with special 1/4" male hex drive. 3-way bit and socket locking flex head ratchet can be used as a low profile ratchet, used with extension bar for deep reach or as a "T" speed handle. (RFB400K)