13-Piece Hex Impact Bit Socket Set with Rail. drive hex impact bit sockets in sizes: 4, 4.5, 5, 5.5, 6, 7, 8, 9, 10, 11, 12, 13, 14 mm. Why Choose Our Hex Impact Bit Socket Set?. Permanent Connection: The bit is firmly pressed into the socket, creating a robust connection that withstands stress without loosening.