Socket head cap screw

Round head hex socket screw

Hex socket head screws with Phillips recess, also known as hex head Phillips screws, socket head cap screws with Phillips recess, or Phillips drive hex screws, are a versatile and widely used type of fastener. They combine the strength and grip of a hexagonal head with the ease of driving provided by a Phillips recess, making them suitable for a diverse range of applications.

Special screw 

Toothed lock washers are a type of washer that has teeth on both the inner and outer diameters. The teeth help to prevent the washer from slipping and rotating, which helps to prevent the bolt or nut from loosening.

Round head screws