I love my USO Flip out that mounts on the rail. The nice thing is I can level a scope in no time with it also since it doesnt mount to the optic. I flip out the level that's mounted on the rail, throw a good digital level on top of the turret, rotate until dead on 0 and tighten down one of the screws on the ring and its dead on in less than a minute. I have compared it against a scope leveling kit and it was the exact same outcome. Also I like the bubble being lower so I can glance down without moving my head/cheekweld to make sure I am level. I thought I would break it off but its been beat to hell and back and still going strong...