I believe he's talking about the clip that holds everything down on a BIC drive plate assembly shaft. Technically, it's an "E" clip. There are several components that are installed on the shaft before the drive plate and then there is a fairly substantial spring installed, and then the clip.
I used to have the hand strength to push the spring down below the groove in the shaft and get the clip on. Age has weakened my hands and I can no longer do it that way. Now, I clamp a small vise-grips onto the clip and the added leverage enables me to put the spring in position, press it down with the clip held in the vise-grips and slide the clip into the groove. Done.
Doug