I live in South Florida and it gets hot down here. Dogs I know should be carrying a backpack with the weight even on both sides, the weight should be carried in the same area a rider sits on their horse...right behind the withers. The last rib and back is the weakest part of the back and should not be carrying any weight. They should be carrying no more than 20% of their body weight. Being in South Florida, a pack mostly mesh would help to keep the dog cool. Reflective is always a plus, and the pack staying in place is very important to maintain the integrity of the dog's back. I would love to have a pack from one tigris that would have that in mind and along with the idea that the pack would be used for the purpose of exercise. I am a Realtor and Pet Sitter. I take a lot of the dogs skating for exercise and to have a pack on the dogs while they are going for a run, will help slow them down and increase the benefits for the dogs.