The Ruffwear Quinzee insulated dog jacket wraps your pooch in lightweight warmth-perfect for breaks between activities in cold weather. Synthetic insulation keeps dogs warm in the coldest weather conditions. The jacket's 50% recycled polyester insulation helps keep your dog warm; its 40% recycled polyester shell material resists abrasion and snags. 3M Scotchlite reflective trim adds visibility in low light. Covered side-release buckles make getting the jacket on and off a breeze. Packs down into an integrated stuff sack. To determine correct size, measure your dog's girth (the widest part of the rib cage.