Rock solid, easy on/off - Kinetic Development Group SIDELOK Cantilever Modular Mount Scope Rings

Awesome mount. Easy to put on and take off. Rock solid when attached. Another reviewer stated it seemed loose, but keep this in mind...as it comes out of the box, the lower half of the rings are attached loosely to the mount, and the upper half of the rings are attached loosely to the lower half of the rings. So if you snap it onto a rail (right out of the box) and wiggle the rings, yeah the rings wiggle but that's just the rings not being screwed into the mount all the way. They assume you're going to put a scope in it, tighten the rings onto the mount, and tighten the upper ring halves to the lower ring halves, which you are. Bottom line this is a great mount.