Weight: 283 g (size UK 5.5)adidas Primeknit is carefully engineered to naturally expand with your foot while you run to give you a more comfortable fit and help reduce irritationboost™'s energy-returning properties keep every step charged with an endless supply of light, fast energySTRETCHWEB rubber outsole is lightweight and elastic, adapting to the ground for stability and working strategically to optimise the unique properties of boost™ from touchdown to push-offTORSION® SYSTEM for midfoot integrity; Moulded 3-Stripes and heel counter for support and optimum heel hugRunner type: neutral; Stack height: 30.5 mm / 20.5 mm (10 mm differential)