These pellet seaters are designed to help push tight pellets into the barrel or an airgun at a consistent depth. This will help seat pellets that are tight in the barrel and leave the skirt sticking out slightly.
There are two sizes, .177 and .22 caliber. .22s also work well for .25 caliber pellets.
All designs have a hole for a keychain or laynard string.
The author hasn't provided the model origin yet.