The XDOG ?Weight and Fitness Vest ? is a health improving vest that helps with building strength, performance, muscle growth, power, speed and overall health in your ? dog. It's also a great tool to help combat obesity in over weight dogs, improve cardiovascular health and reduce energy faster for high-energized dogs. SAFE, COMFORTABLE WEIGHTS BAGS - THE XDOG vest uses weight bags that can be filled with sand or copper bb's.These weights are much SAFER vs METAL BAR WEIGHTS that others use because ours can MOLD and COUTURE with the body during movement. They don't cause pressure points and are less DANGEROUS than a heavy bar weight. quality, LIGHTWEIGHT, BREATHABLE MATERIAL - The XDOG Vest is built for ? durability during workout however its material is lightweight and doesn't weigh down your dog allowing a natural, fluid movement during wear. The vest is also water-proof. SECURE SNUG, ? COMFORTABLE FIT - Because the XDOG features both alligator clips and velcro to help secure the vest on your dog's body you won't need to worry about any Inches side to side Inches or Inches rocking Inches movement of the vest especially during high-intent running or exercise. The vest will securely stay in place 100 Percent and and will NOT interfere with your dog's natural movement. FRONT SHOULDER WEIGHT PLACEMENT - The XDOG Vest is the only vest on the market today that features front shoulder weight placement allowing them to build stronger muscles and strength on the front legs for improving explosive takeoff and speed. Don't expect to see this feature on other dog weight vests. Many of them have ignored the front legs completely with weight placement only placed on the back.