One end of the socket is a square hole, which is used to connect the ratchet wrench, L rod or slide rod. There are three common square specifications: 1/2 inch, 3/8 inch, and 1/4 inch. One inch is about 25.4 mm, 1/2 inch is about 12.7 mm, 3/8 inch is about 9.5 mm, and 1/4 inch is about 6.35 mm.

One end of the socket is a regular hexagon hole or a regular hexagon. The hexagon is a common socket. The hexagon is like a ring wrench, commonly known as a ring socket.

Sleeves can be used by hand and pneumatic, which means using hand to apply force, while pneumatic is used on pneumatic gun, which means pneumatic wrench or electric wrench.

Generally, the manual sleeve is thinner, while the pneumatic sleeve is generally thicker than the manual one, because the impact force is relatively large when the pneumatic wrench is turned.

Sleeves can also be divided into long sleeves and short sleeves. The common sleeves are short, while the long sleeves are longer than the common ones. In some places where the screws are longer, the nuts can be better clamped, such as 1/2 sleeves. The common sleeves are generally about 5cm, while the long sleeves are generally more than 10cm.

The spark plug sleeve is about as long as the long sleeve, but it is generally very thin because the location of the spark plug limits the thickness of the sleeve.