The Back on Track® Multi Season Dog Coats are waterproof and breathable, a high quality polyester garment, lined with a unique FIR fabric called Welltex. This gentle therapy allows an increase in blood circulation which can help muscles and joints to stay supple and maintain mobility, so that the dog can remain as active and as comfortable as possible. This offers 3000mm of waterproofing, allowing the fabric to release excess heat and water vapor. Length: Measure back from withers to root of tail. This is our best selling winter and wet weather coat for dogs of all breeds and ages.