I only had it on the back of a multi-ball racket. I haven't used it much. The black marks on the sponge side are from rubbing during multi-ball drills. I think there are no problems with use. 157 x 150mm I have other items for sale. No case. If you want a case, add 150 yen. If you want a case, please comment before purchasing. If you purchase by September 30th, I will include a case (free of charge).