Things I liked: Fits perfectly on my FX-Revolution Rifle Barrel. I used it to mount a laser. In order to install, I had only to temporarily remove the Muzzle Chamber (semi-auto function), slide on the barrel clamps and reinstall the muzzle chamber. Use masking tape on both barrel and muzzle chamber to insure proper linear location and angular alignment.
Things I would have changed: Maybe a few more holes for adjustment. Perhaps a little on the expensive side.