Just a simple hold down clamp for a #20 biscuit joiner slot. It allows the user to hold the workpiece firmly to the spoil board without obstructing the top of the wood. Of course, you need to have a biscuit joiner/plate joiner or a comparable jig on your router table to cut the appropriate biscuit slot into the side of the wood piece.  

The hole in the clamp is sized for a 5/16 bolt, though a 1/4 bolt will also work.  I recommend that a washer be placed between the clamp body and the knob or nut.

Sold as a set of 10 because shipping on a single unit would be unreasonable.

NOTE - This is for the clamp body itself.  It does not include bolts or knobs shown in the pictures.