Needs 2 pieces of 30mm diameter neodymium magnet on the 3d printed mounts and 2 pieces of 30mm car fender washers on the controllers to make em stick.
Magnets:
https://www.amazon.de/-/en/Neodymium-Sinking-Magnets-Permanent-Crafting/dp/B07B65VN88/ref=sr_1_1?
Double sided tape:
The washer you should be able to source from every local hardware store.
The magnets are a tight fit and need quite some pressure to be forced in the round cutout.
You can glue the magnet into the holder in addition if you wanna it to be super secure but should be totally fine without it as well. ( friction fit)
With some double sided foam padded tape attach it to the right height when you grip behind your waist.
For Pico 4 controllers you can use my other design and simply glue the washers to the bottom of it:
https://www.printables.com/model/326408-pico-4-knuckle-strap-stand
print with supports from the print bed up.
The author marked this model as their own original creation.