The caster wheels sit in the felt pads but not snug so when you move/roll the chairs they come right off. The caster wheel comes off when the chair is rolled.
Bought these for around same price of variety pack. Similar in appearance, but 4x the number of rubber feet and screws as this one. I like the washer in the middle of the feet and also that they came with stainless steel screws.
Rubber is just the correct amount of hardness. I find them useful not only for cutting board but for many other things such as furniture or small electronics.
The plastic pieces bend easily and allow the screws to scratch the surface. This is defeating the purpose of the kit in the first place.