Disclaimer; I needed help from a friend on these boards to identify this item. So please excuse if I just parrot amateurishly what they told me.

This is a Mauser 88 magazine reduction with spring and screw for holding the cartridge retaining lip on the left side of the receiver (just like on a Mosin action). The lip itself is not included but would be a simple part to make. See pictures!

This is a original German military part for the M 88/05 rifle rebuild to make possible using M 98 stripper clips instead of the original Mannlicher en-bloc clips. The German military acceptance stamp is still visible (pic 3).

Asking price? How does 40€ plus postage sound? Or tell me I'm completely wrong, I'm embarrassingly illiterate when it comes to vintage accessories like this!

The item is in Finland.