Our benches have concrete tops and the trg spiked feet were just getting scratched up, even on top of a thin yoga mat I tried shooting on. I took a rubber sanding block and used the wedged shape edges on either side. With a little carving and filing, I came out with two rubber feet that grab a slick concrete surface and protect the spikes from getting worn down. I carved them so that The profile of the steel feet keeps them from moving with a couple zip ties. Btw they work well on dirt and grass surfaces too. Pm me if you want some pics.