This kit includes 4x rubber feet with #4-40 screws and nuts for mounting.
These are basic rubber feet. They have good grip and are very economical. Install on individual modules (like the breadboard modules) or put them on a backplane to make it more pleasing to work with while at a workbench. We also include these on some of our kits for cases.
Please see our vibration-absorbing feet if you would like something fancy.
0.5" diameter. 0.25" thick.