The Manfrotto RC2 quick release system is one of the most popular in the world for photographers. Its only real competition for tripod mounting supremacy is the Arca-Swiss system. But while very useful, the Manfrotto RC2 base (otherwise known as the Manfrotto 323) onto which your plate mounts has a fatal flaw. The underside of it is not flat.
So, if you want to mount it to a cage, or stack it on top of a plate for a different tripod system, you may face something of a challenge. Fortunately, one enterprising user by the name of Eric Hasso over on Thingiverse designed a solution that can be 3D printed. The folks at LensVid are quite partial to the Manfrotto 323, so they decided to check it out.