Our Most Advance Dog Coat.The Outershell is waterproof,microporous, 3-ply nylon shell with a DWR rating of 50lbs/sq".Lined with thick 450gm black polar fleece. The Strechy neoprene chest panel make for a comfortable fit. Small 15-18" Medium 19-23" Girth, Large 24-28" Girth. Measure just behind the dogs front legs and all the way around the chest. This measurement in inches will give you the girth. Other sizes available special order.