Ordering one unit of this product gives you one clear relegendable cap and one squared edge Model F / Model M compatible stem. The stem (the gray piece) is only compatible with relegendable caps. It will not work with other Model M or Model F caps (the top part of the key if the key is two piece).
The stems are the extremely rare squared off edge type which was a limited production run used on some of the original IBM 4704 banking keyboards. The relegendable caps allowed banks to put in specific function keys before the days of the GUI for IBM mainframes and terminals.
The caps are used and yellowed with scratches and other discolorations, a typical example of which is pictured. The cap plastic is very brittle.
The key stem’s squared off edges allow for the paper label edges to look better and for the paper labels to fit more snugly inside the transparent cap.
I have a very limited supply (about 20 total) and this item will sell out fast. I will remove the listing once they have sold out. This is the only place to get these, unless you buy an original 4704 keyboard that happens to have these caps (if you can find one!).
You can access a template for printing your keys here: https://deskthority.net/workshop-f7/ibm-4704-model-f-model-m-transparent-key-template-t9794.html