These wheel chocks can be used to stop chairs with caster wheels from moving. This may be desired when playing flight or driving simulator games. Pushing against gas/brake or rudder pedals while sitting on a chair with wheels is not ideal.

I created this so that there is no need to lift the chair to use these.

Use foam tape under the chock to grip the floor. 

To use, push down on the chock to compress the foam tape, slide under the wheel and release. Using just two on two of the 5 wheels on my chair provides sufficient stability for my gaming purposes.