RUN LIGHT, HYDRATE SMART. Designed for high-mileage runs, this lightweight dog hydration vest keeps your running partner cool, balanced, and fueled with two included Ruffwear soft flasks and zippered storage for essentials. FIND THE RIGHT FIT WITH EASE. Not sure which size to choose? Check out our sizing chart image and how-to-fit video to help you measure your dog correctly. A proper fit means more comfort, control, and confidence on every adventure. ZERO BOUNCE, TOTAL COMFORT. Adjustable vest-style fit hugs the body for stable, chafe-free movement mile after mile. Tested by runners who say it’s like their dog’s second skin. STREAMLINED TRAIL DESIGN. Minimal bulk, breathable mesh, and bluesign-approved materials make this the lightest Ruffwear running pack. Ideal for endurance, not load carrying. SAFE FROM DAWN TO DUSK. Reflective trim and a rear light loop for The Beacon keep dogs visible in low-light conditions, giving runners peace of mind on early or late adventures. BUILT FOR THE LONG RUN. Reinforced leash loop, secure YKK zippers, and durable webbing stand up to years of training miles, tackling the roughest terrain without fraying or shifting. You have your favorite running vest – this one’s your dog’s. The Trail Runner Running Vest opens up new territory by making it easy and comfortable for your running buddy to carry their number 1 trail essential: hydration. Mindful design and material choices keep the vest breathable, balanced, and bounce-free. Two zippered side pockets hold the two included Hydrapak soft flasks, and you can stash the Trail Runner Bowl (not included) and pick-up bags in the top zippered pocket. A reinforced webbing tow loop at the rear offers a strong leash attachment point, optimally positioned for dogs that like to take the lead. Hydrapak Soft Flask included:: 2 x 360 milliliter for XS; 2 x 500 milliliter for size S - L/XL.