This is the 5 round factory 12 gauge magazine for the Derya Mk12 shotgun.
Also fits the Derya Mk10 and shares the common rear lever last round hold open format common to many Turkish shotguns.
Manufactured from heavy duty steel with a black coated finish the magazine is fully strippable for cleaning if you remove the polymer baseplate.
Also available in 10 and 19 rounds sizes.