Summary

I wanted some holder which can be mounted to underside of desk or shelf (in my case, the monitor shelf/stand) and hold my Surface while it's charging.

Designed for Surface 3 with attached keyboard, but would work for any device with thickness 15 mm or less.

You have to print multiple pieces, usually 4 or 5, depending on how do you want the tablet mounted. Depth of my monitor shelf is equal to depth of the Surface, so I don't need depth stop. If it would go under bigger desk, you would need one additional piece to stop the tablet from faling trough.

Remember that you have to have some way of connecting the charger. Surface has the power connector on side, so I had to put the front left part way to the side, to allow the connector going trough.

I highly recommend to screw the holders from bottom with wood screws. The photos show mounting with industrial double-stick tape, because I have to take my shelf apart to screw those screws in and wanted to test it beforehand (and the shelf is just about 15 cm high). If you'll mount it under high desk with tape and your tablet will fall down, don't compain :).