This is the Armscor Rock Island VR60 / VR80 12-gauge 9-round magazine.

This also fits common AR-12 shotguns:

• Panzer Arms Bullpup BP-12 G2
• EGX500
• AR-12
• SCRXII
• AR Twelve G4
• G-Force Firearms
• Bora Arms BR99
• BR99X
• BR99S
• Barak Arms GFY-1
• Typhoon F12
• Typhoon XII
• Black Aces
• Radikal ARMS MK Series / NK Series
• RIA Imports
• Aksa CF-12
• BH-12
• BSA-12
• BP-12
• Tokarev
• SDS