EM TRI N 2 62% Synthetic, 38% Textile Imported Rubber sole The Tri N2 is part of the Project E:Motion series which has been engineered to provide the smoothest running experience; Women's specific fit. Inside is silky smooth for sockless racing comfort; Insole has a deeply cupped heel that securely cradles the foot; Outsole is high-mileage durable and has a lug pattern for traction. The Tri N2 features our Dynamic Offset technology for a lively and smooth ride that eliminates forefoot slap and reduces shock; The Tri N2 is neutral and has a cushioned level 2 midsole thickness. The Tri N2 has a low 4mm drop and a combination of shock absorbing and energy return foams; At 9 ounces, it is light-weight, yet cushioned enough for Ironman distances. 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