The North Face Thermoball Traction Mule 2 Rubber sole ThermoBall insulated slip-on with a grippy rubber sole Lightweight, compressible ThermoBall insulation retains warmth in wet, cold conditions Durable, water-resistant, 100% recycled P.E.T. ripstop upper 40% recycled rubber outsole for supreme traction Rectangular baffle pattern links directly with the ThermoBall jacket