Because there are many work at a low position, I bought it to stabilize my body with my knees on. It certainly does not hurt even if I put my knees on the floor of the checker plate or the scaffolding board, but the semicircular spherical resin fixed on the surface of the pad slips with the corocoro and the body is not stable. It seems not to be suitable for the application I am seeking. Two rubber bands with Velcro can also be fixed firmly to the knees, making products is never bad. I thought that it was enough if there was no wear-resistant processing on the surface (with no semicircular spherical resin part) only on the pad.
It is the one with the largest size that I bought. The material of the surface is hard to break even if rubbed on the ground etc. It seems that it can be used for a relatively long time. I think that the back side probably contains urethane, but I did not feel pain even with the work on my knees. There are two bands with Velcro, so the feeling of wear is perfect. It did not fall off. As a demand improvement point, I think that it is good to be able to fine-tune the degree of adhesion to the knee if you can make a range more stopped with Velc tape. As a whole, it is a good feeling, so it is recommended for traders who have a lot of work on knees.