Pearl iZUMi Men's EM Tri N 1 Running Shoe 100% Synthetic Imported Rubber sole The Tri N1 is part of the Project E:Motion series which has been engineered to provide the smoothest running experience; Inside is silky smooth for sockless racing comfort. Insole has a deeply cupped heel that securely cradles the foot; The Tri N1 features our Dynamic Offset technology for a lively and smooth ride that eliminates forefoot slap and reduces shock. The Tri N1 has a low 1mm drop and a combination of shock absorbing and energy return foams; The Tri N1 is neutral and has our most minimal level 1 midsole. At 8.5 ounces, it is extremely light-weight, yet cushioned enough for Ironman distances; Outsole has strategically placed rubber pads for traction and durability. Seamless upper is engineered for quick and easy transitions with a stretch bootie, speed-lace construction, and a large heel pull-loop; Features two layers of mesh - one is extremely open for breathability and drainage while the other is fine to keep out