Chrome vanadium 6150 steel. Includes 48 x 25mm bits (PH, PZ, Slotted, Hex, Trx and Security Trx); 7 x 76mm bits (PH, PZ, Slotted and Trx), and quick-release bit holder. Chrome vanadium 6150 steel. Includes 48 x 25mm bits (PH, PZ, Slotted, Hex, Trx and Security Trx); 7 x 76mm bits (PH, PZ, Slotted and Trx), and quick-release bit holder.