This is the SGM 25 round drum magazine for the Vepr-12 shotgun.
Also fits the Armsan RS-S1 and Citadel RS-S1 out of the box with no modifications required.
Manufactured from a tough glass reinforced polymer it has a clear rear panel facing the shooter for round count.
We have yet to try this out on an Armsan RS-S1, we hope to be testing it soon.