.45 acp LWD 2 port ss barrel for your g21/sf. put maybe 2 mags worth when i first got it and soon switched to a threaded barrel....so this one is just sitting in the safe. however, it did work well. it really kept the muzle down between shots aiding in faster follow-ups aswell as a softer recoil impulse. coulnt tell an accuracy difference between this and the g21sf OEM barrel.....i tried but my accuracy results were about the same iether way.  $100 shipped. email me at kendapp@live.com