When you ride indoors, you need a stable spot for your trainer, one that will keep your trainer from rocking back and forth. The BKool trainer mat is designed to keep all your contact points on the ground so that all you need to concentrate on is pedaling. The mat is constructed from a heavy rubber compound, and is easily wiped down after your workout has you drenched in sweat. The BKool trainer mat is available in One size and in Black.