Sizes Available: 2FT6, 3FT, 4FT, 4FT6, 5FT & 6FT. Orthopaedic Reflex Foam Spring Firm Mattress. This mattress is also an outstanding choice for those with allergies or respiratory conditions. The foam is both anti-microbial and dust mite preventative, making it particularly beneficial for asthma sufferers and those with sensitive airways.