The Rocket Anchor snaps into place (left).  Three popular boxes showing mounting options.


These photos show typical mounting using screws and nuts provided.  The support rim on the bottom can be easily shaped to fit the contour of almost any chalk box.  Mounting the sheath on the Starrett® box shown below does not require any trimming.  Sheath Instruction Manual

Tajima® box may be a little more challenging but mounts with the same proceedure with trimming the support rim for best fit.  The result proved to be solid and trouble free even with having to split the case to fish out the string.  Notice one screw insert to maintain alignment while drilling the second hole.