The four corners are darted to allow the pad to fit different sized crates. The bolster slides up the edges and fills in the corners for a perfect comfortable fit. The ultra-plush fleece is soft and cozy for ultimate comfort. The bottom has a “stay-put non-slip fabric One size to fit multiple size crates Bolster slides up the edge and fills in corners for ultimate crate comfort Stay-put non-slip bottom for stability Ultra-plush fleece feels like sleeping on a cloud Completely machine washable.