1. Selection of electric drill bit size. The size of household electric drill bit is usually 20mm. However, the details depend on your own situation.
2. Selection of additional functions of electric drill: the same type, there will be some additional functions, for example, the type with R indicates that the drill can rotate forward, and its advantage is that when the forward rotation is not possible, it can be converted to rotation; there is E in the type It shows that the electric drill can be adjusted in speed. When the high speed is not required, it can be adjusted to low speed. Of course, the more functions, the price will increase.