I have a used Marvel Unit 1. This is their most accurate conversion. Fixed barrel. Test target shows 1/2" at 50 yards. I have a sighted top end and a railed top. Red dot sight included. I have the extended barrel and compensator, but I lost the set screw for the comp and have a call in to Marvel for a new screw. 3 magazines. There are a couple of scratches. Priced accordingly $325. I can ship it for $10, or FTF in Tulsa or Owasso. No trades please, except perhaps a Trijicon RMR.