The ultimate in Canine Fitness Training. The only FUNctional canine fitness apparel that lets your dog do more! K9FITvest is four vests in one, making it easy to incorporate gradual therapeutic resistance training, cooling, sensory integration and safety into all of your dog's activities. Stair-step resistance traiing program helps direct progressive strengthening of a dog's body from the inside out for companion pets as well as Canine athletes. Simply put K9FITvest on to increase the intensity of your dog's activities and increase fitness. Innovative shape offers body conformation and allows for a wide range of exercises. Gravity enhanced to boost calorie burn, decrease workout time. Improve strength, speed, performance and body awareness. Low level therapeutic resistance for dry land and hydrotherapy rehab options. No shifting, sliding or chafing. Cold gel packs sold separately offer cooling relief. Made with reflective material helps visibility in dim light. Professional notice: if your dog has had or is experiencing back or hip issues, please do not use the K9FITvest with weights. Consider purchasing the gel packs to use with the K9FITvest. Please seek professional guidance to rehabilitate your dog the right way. Breathable 4-way compression material. Resistance weights. Integrated chamber for weights or cool packs. Motion control design.