This gland snaps into place around the power lead at the point where it passes through the entry point in the chassis
It can be difficult to fit (or it might snap into place on your first attempt); a special tool is available to assist matters if you struggle
The purpose of the gland is to prevent the power lead wires being strained, or even torn from their connections, in the event that the power lead is yanked or pulled
For this reason it is important to refit the gland if you change the power lead