Bits made of premium S2 alloy steel for superior hardness and great rust-resistant. Chrome vanadium steel socket for high strength and superior torque. | Press the bit directly into the socket to make a permanent connection. The carefully pressed process ensures that the bit is straight and fits tightly, the bit will not loosen over time or under pressure. | Four detent grooves in the socket drive end provide a secure connection with spring-loaded detent balls of a drive tool, ensures the sockets won't slide or drop. |