BREATHABLE MESH: Made of high quality cushy breathable polyester mesh. NO PULL & CHOKE FREE: Pressure is evenly distributed over your dogs chest to avoid any choking. EASY ON & OFF: Adjustable chest belt and quick release buckle for easy on & off. Sturdy D-ring for easy leash attachment. SIZING: These are for the smaller breeds, our 12 lb shih tzu wears a size medium. Neck is not adjustable and has to be able to go over your dogs head. 100% SATISFACTION GUARANTEE: We stand behind our products, if You have any problems feel free to contact us.