Orthopaedic mattress: Get a reflex memory foam orthopaedic mattress. Sizes: Choice of six sizes (see below). Forms to your shape: Designed to form to your natural body shape and support your body during sleep. Depth: Firm with a depth of 6″ (approx). Hypoallergenic: Hypoallergenic and anti dust mite. Get a great night’s sleep: Feel the benefits almost immediately.