+1 to the felt type .

I've got them on all of my 4 pins and they work great .

Some tips though are to check your legs to make sure they don't have any burrs / sharp edges  and when tightening up the leg bolts - don't overdo it !! You only need to just nip them up firm . The more you tighten the more you're going to pull the steel leg into the timber cabinet .