The ProtectEase Cooling Comfort Fitted Waterproof Mattress Protector for a Twin size bed measures 39" x 75". Made of Polyester and Nylon, it offers all-season insulation with a GSM of 150 to 300. This white mattress encasement is machine washable, hypoallergenic, and stain-resistant. Suitable for waterbeds, it features cooling properties and is part of the Nestl Bedding Mattress Protectors line.