R/C Motor Mount for 12mm Tube

Standard Motor Mount for 12mm tube frames.

There are three different mounts, all for 12mm OD tubes:

From weakest to strongest:

Short two-piece clamp mount.
Long one-piece clamp mount.
Long set-screw mount.

I've found the set-screw mount to be the only one reliable enough for my larger (8" prop) quadcopter applications, but YMMV.