This three-layer chest panel features Ruffwear&';s Swamp Cooler(TM) Tech that uses evaporative cooling to efficiently disperse heat from the dog&';s core when exploring in warm temperatures. To activate, wet the Swamp Cooler Core with water, use the hook-and-loop sleeves to attach it to the chest and belly straps of the pack or harness, then hit the trail! SWAMP COOLER(TM) TECH Three-layer construction that absorbs water and promotes an evaporative cooling effect for warm-weather exploring. EASY ON/OFF Easily add as cooling belly panel to a compatible pack or harness with hook-and-loop sleeves. ADD-ON TO HARNESSES & PACKS Compatible with Ruffwear&';s Web Master(TM), Approach Pack(TM) and Palisades(TM) Pack Measurement is around the widest part of the rib cage. The size should match your existing compatible Ruffwear gear. Small - 22 - 27 in (56 - 69 cm) Materials & Care Materials Outer Layer: Polyester air mesh Middle Layer: Polyester non-woven Lining: Dry-weave polyester mesh Made in Vietnam Care Secure fasteners Wash in cold water Gentle cycle Mild detergent Air dry