This is a Armscor Magazine known as the ACT-MAG chambered in 45 ACP, model 44522.
This ACT-MAG for Sig Sauer P220 is a standard factory replacement magazine. This magazine has an 8 round capacity" is chambered in .45ACP and features a steel magazine body with a blued finish.
Features:
Steel Magazine Body
Polymer Base Plate
Perfect Fit and Operation