These are clear, self-adhesive silicone bumpers 8mm in diameter and about 2mm tall. These bumpers raise your PCB or project up off your desk which helps prevent short circuiting from bits of scrap wire floating about or setting a project down on a conductive surface. They also prevent your enclosure or PCB from sliding around. These clear silicone bumpers come in strips of 5.
Note: For some reason our supplier has begun sending these bumpers to us in strips of 5 instead of 4. Hey, we aren't complaining. Enjoy!