You don't see these very often. Oly Arms, Simunitions 9MM, 20 round magazines. All 5 as a set for $100 or $25 each shipped.
These will work with Oly Arms 9MM uppers. Oly Arms was selling these for use with their 9MM uppers just prior to the Ban in '94. They only work with Oly uppers as they eliminate the need for a mag block which would also eliminate the ejector on the mag block. Oly uses a spring ejector mounted in the upper receiver.Price Reduced