This trail engine runs smooth and efficient without knocking, overheating or overload. The Octane by Merrell incorporates significant elements of Merrell trail technology, from heel/toe Trail Balanced™ last to dual-density Trail Alignment footframe and acclaimed Merrell Trailspring™ tuned tubular supports system. Closefitting airmesh upper vents and drains on demand. A Vibram® Full Speed II™ sole centers and the heel and encourages forefoot propulsion. End Use: Adventure racing and trail running on moderate to backcountry terrain. - Neutral Trail Shoe - Merrell Exclusive Trail Balanced™ Last - Slip Lasted Construction with EVA Insole - AirMesh Upper with Synthetic Leather Trim - 3m™ Scothlite™ 360° Reflective Trim - Bellows Tongue - Ventilation and Drainage Upper Design - Forefoot Protection Upper Design with Gaiter Hook - Anatomical EVA Footbed - Trail Alignment System Dual Density Molded EVA Footframe (men) - Q-Form™ Triple Density Compression Molded EVA Footframe (women) - Injection TPR TrailSpring™ Structural Cushioning and Support System - Gaiter Strap Channel at Arch Bridge - Air Cushion® EVA Midsole - 5mm Sole Lug Depth - Vibram® Full Speed II™ Dual Density/TC5+ Rubber - Vegan Friendly Footwear Men’s Weight: 1 lb. 6 ozs. Women’s Weight: 1 lb. 4 ozs. Men's Sizes: 7-12,13,14,15 Women’s Sizes: 5-11