Carry bag: Includes a handy carry bag for added convenience. Topper: Get a Silentnight mattress topper. Anti-allergens: Non-allergenic and machine washable. Sizes: Option of a single, double or king. 20 channel: This innovative 20 channel topper is filled and quilted with spring-like coiled fibres. Straps: Finished with elastic straps which simply slide over each corner to fit your mattress perfectly.