These covers are lightweight and compact. They help create the "den" effect that is such an important part of crate training. Made from a nylon material with clear vinyl door with zips. Front door opening only for 50cm and 61cm sizes. Other sizes come with front door and side door openings. IMPORTANT: Althought the Savic crate Covers are intended for the Savic Residence Crates, their suitibility for the Savic Cottage Crates is as follows: Cottage Crate Size Suitibility Small Fits, but requires tucking in at the bottom MediumFits perfectly Intermediate Fits, but requires tucking in at the bottom Large Fits, but requires tucking in at the bottom X-LargeFits perfectly GiantFits perfectly