The Ruffwear Grip-Trex Pairs - 2.75in. Dog Boots are paw wear for dogs who hike, bike, run, or explore the great outdoors with their humans. These high-performance boots feature a rugged and resilient Ruffwear-designed Vibram outsole that provides exceptional traction on varied terrain. Breathable mesh upper provides ventilation and keeps dirt and debris out. Closure system combines hook-and-loop with hardware, cinching around the narrowest part of the dog's leg to provide a secure fit. Just as you would with your gear, check closure system and adjust fit as needed 15 minutes into your activity and throughout the adventure. Note: Set of TWO boots. Many dogs have wider front paws than rear paws. Boots are offered in sets of two so you can order the appropriate sizes for a good fit on both the front and rear paws. Measure paws across widest part of paw when bearing weight. Measure ALL paws. If between sizes, size down.