I purchased from Home Depot a small plastic insert for the space in my fuse box.This corresponds to the details that are in the box.However, the pieces does not fit right and fell down into the wall.I had another and placed it there, but if anyone touches it... it will either fall out or fall into the wall space.The Unit says QC for the piece.Does anyone have any suggestions on how to get a piece that will fit that fuse box.The Depot says "That is the only one".Thanks

You mention "fuse" box. Breaker box? QC is a breaker designation. This is the insert when the breaker is removed? Single or double pole? Square D box?

The package said Square D QO but it does not fit correctly. Falls out of the space.
The specs are: QO Load Center, Cat. No. QOC-12 Series F-1 QO Circuit Breakers QF Fusible Units Underwriters Laboratories, Inc. Electric Cabinet Front
Issue No. G 95 LL5988W.

Not the cheapest, but you could buy a couple of 20 Amp Breakers, Maybe around $6 each, and if a working one fails, you already have a breaker, just need to swap the wire.