Materials Soft stretch poly base, woven nylon straps, and coated carbon steel D-rings Product Dimensions & Specs Harness Without Neck Buckle: XS: Neck = 8"-11", Chest = 12"-15" S: Neck = 10"-14", Chest = 14"-22" M: Neck = 12"-18", Chest = 18"-28" L: Neck = 16"-21", Chest = 24"-38" Harnesses With NEW Neck Buckle* (Seafoam, Moss, Orchid, Black, Lilac and Blaze Only): XS: Neck = 10"-11", Chest = 13"-16" S: Neck = 12"-14", Chest = 16"-22" M: Neck = 15"-18", Chest = 20"-28" L: Neck = 17"-22", Chest = 26"-38" *New launches feature an additional neck buckle for maximum adjustability, easier on and off, and a better fit for most breeds. Sizing has changed slightly with this new design, so please refer to the listed measurements for the best fit.