At my son's school some kids think it is fun to unscrew the valves of the tires of the bikes so you have a flat tire. It is a not uncommon issue also at busstops or everwhere where many bikes are parked.

This lock will prevent this from happening. Put it over the valve and lock it with self-locking nuts and bolts.

It fits standard valves, not the french ones.

No

Doesn't Matter

0.2mm

The holes are 3mm, so either use a bolt small enough or add some screw-thread.

Tinkercad