Summary

This uses magnets to hold the door closed on the D4S.
(D4S or other steel frame bot.)
Non-invasive assembly.

Instructions

2 Piece Button Assembly Sized for 19mm / 3/4" disc magnet.
1 Door Stop using 1 (19mm / 3/4" disc magnet) and 1 (3/8"x7/8"x1-7/8" 9.5mm x 22mm x 47mm). Magnets bought a local Hobbytown USA.

Note: The buttons are slide together assembly with a tight fit, you may need to pound on it a little. I tried to make the items fit tight so no glue or fasteners would be needed. Also check you magnet poles before final assembly. Once put together there is no turning back, just making a new part.

Wanhao Duplicator 4S Door Close Stops