This is a sliding sheet for speed skating practice, used indoors to train your core by sliding your feet left and right. I purchased it on Amazon and used it a few times, but it was too challenging for me, so I'm selling it to someone who needs it. It comes with a yellow sheet and a pair of special sliding socks. The back of the sheet has a non-slip treatment, so only the surface of the yellow sheet is slippery. I've only used it a few times, so there's still some white powder on the surface, and the socks will get slightly white, but it slides without any problems. The sheet size is 50cm (vertical) x 180cm (horizontal), including the rubber stoppers on both sides.