The big size of 54" W x 58" L can cover the entire rear seat for most cars and SUVs. Nonslip Seat Cover: Designed with anti-slip rubber backing, 4 headrest snap buckles, 2 seat belt openings, using dog belts to keep your dog on the seat and protect your dog from injury or slipping during driving, plus 2 seat anchors, which are further firmly held in place to prevent the dog seat cover from sliding around.