This base holds 2 Magswitch 150 clamps, and is designed to attach to the Magswitch universal track, which can act as a fence, hold clamps, hold-downs, featherboards, etc.  The mounting hardware in the photo is included with the universal track; I didn't create it, but tried to use it as it was apparently intended.

The design is in Sketchup.  I built one copy, which works great, but needed to be filed slightly to give a little more clearance for the switches.   The model has been updated to provide 1mm more clearance.  The print required the full width of my Anycubic MegaPro.  Wider would probably be advantageous for stability, but I went as wide as could.

Printed in PLA, with 30% infill and 4 side walls, to allow for tapping and/or woodscrews.