Road Runner Sports Thin No Show 3 PK. Special dual layer moisture removal system which moves moisture off the skin to the outer layer: Keeps feet dry, comfortable and blister free Additional breathable mesh: Keeps feet cooler &amp; drier Flat toe seam: Helps eliminate blisters 3D Fit: Sizing developed on 3D foot model ensuring a custom fit In-step hugging arch band: Helps eliminate blisters MicroZap Antimicrobial: Fights odor causing bacteria