What could it be? 

Order one, find out @russ 😉 
Its something else of great use in guitar building (and other less important woodworkery, potentially!), built to the usual high Bagpress standards @darrenking.

@Russ – I got the first drill-perpendicular-holes gadget that you posted, and a variation on the second version. They work in some situations/positions, but won’t work in all.  The main problem is ensuring that the guide fits flat on the…   Read more»