S - Fits dogs 22 lbs to 34 lbs. Chest Diameter 22" - 27.5"M - Fits dogs 35 lbs to 60 lbs. Chest Measuring a Diameter 24.5" - 30.75"L - Fits Dogs 61 lbs to 100 lbs. Chest Diameter 27.5" - 35.75"MAXIMUM VISIBILITY: Providing your pet with maximum visibility in both daytime and low-light conditions， the SafetyPUP XD dog vest helps prevent accidents， sheds moisture and guards against minor abrasions. 1) Reduces the chance of automobile-related injury， 2) Helps prevent hunting accidents when camping or hiking， 3) Excellent for working dogsEXTREME DURABILITY: The SafetyPUP XD vest is built from premium materials and engineered to stand up to tough environments without ripping or unraveling. 1) Ultra-durable 300D Oxford Weave fabric， 2) Reinforced stitching，3) Resists rips， tears， and abrasions，4) Repels water and soilERGONOMIC AND COMFORTABLE: The SafetyPUP XD dog vest keeps your pet cozy while eliminating discomfort and irritation. 1) Fabric interior is soft and smooth， 2) Ergonomic design reduces chafing and irritation， 3) Extended Velcro? strips for a customized fitIDEAL FOR OUTDOOR USE: The SafetyPUP XD blaze orange vest excels in natural settings and makes an excellent hunting dog vest. 1) Hi-Vis coloration differentiates your pet from game or wildlife，2) All-weather construction keeps out moisture， 3) Repels ticks， burrs， and poison oakSATISFACTION GUARANTEED! We stand behind our product 100%. If you don't LOVE the SafetyPUP XD pet vest， we will happily refund your money! Try it now with zero risk! You've got nothing to lose. Keep your pet safe， and secure in any environment. Don't gamble with your pet's safety - purchase your SafetyPUP XD reflective dog vest today!