These top rail end caps that fit Kirsch Medallion horizontal 1" mini blinds. 

These caps insert inside the end of the top rail. Then, they snap into metal mounting brackets.

Plastic. Sold individually.

These parts are discontinued and no longer made. They are available in a variety of colors in both right and left sides. However, some colors may only be available in one side and not the other. Quantities are limited and they will not be restocked.