The Platinum is an 18cm (7 inch) Medium-Firm Mattress that is specifically designed for use with the upper bunk of Julian Bowen Bunk Beds due to height restrictions. A superior quality mattress with a low profile construction. Dimensions: Single: Mattress Length: 191cm. Mattress Width: 91.5cm. Mattress Depth: 18cm. Weight: 12.5kg. .