This is a set of split pins for watch bands. The split pin is part of the belt connecting to the links.
There is no need to spare a cotter pin to remove the length of the belt accidentally or to replace it due to long-term use. This product is convenient for those occasions.
This set comes with 18 different diverter pins from 6mm to 23mm, so it can fit most watches.
It comes in a compact plastic case so you can store it without any worries.