This is a waterproof mattress pad from Nitori. It comes in single and double sizes. I measured the larger size, and it's about 125 x 195 cm. I think it's about the size of a semi-double. I bought it when my child was potty training, but they ended up not having any bedwetting incidents and grew up, so I'm selling it now. The elastic on the double size is loose. The single size doesn't feel as loose. I bought the single size later, so it may have been used less than the double. This is a used item, stored at a private residence. Please understand this before purchasing. Nitori Waterproof Mattress pad Waterproof sheet Childcare Nursing care Pets Bedwetting Diapers Single Semi-double