Dog Mate Dog Doors are suitable for a wide range of dog breeds. The medium and large doors feature robust 2-way locking panels for security. All flaps are fully brush sealed with magnetic closure for total weatherproofing and minimum energy loss from the house. Super strong, lightweight flaps are suitable for dogs small and large. Wall installation is possible using standard sheeting to line the wall. Available in medium & large sizes. Manufacturer offers a 3 year guarantee. The medium door is suitable for Spaniels, Terriers, Poodles, etc. up to 18in shoulder height.