Name: screwdriver bit socket, hexagonal drill bit socket.
Material: alloy steel.
Colour: silver.
Surface treatment: electroplating.
Application: for a variety of 4mm size specifications of the screwdriver bit, and suitable for a variety of electric drills, used in a variety of scenarios for the installation of items.
Package content: contains 5pcs hexagonal drill bit sockets, size 28x6mm/1.1x0.24inch, inner diameter 4mm.