FirstGear TPG 37.5 Tech Men's Liner Street Bike Racing Motorcycle Gloves - Black / Medium The 37.5 Glove Tech Liners are the ideal layering piece for yourriding gloves. With its extraordinary wicking properties, hands stay warm when its cold and cooler when its hot outside. They dramatically improve the performance of any waterproof-breathable gloves. 37.5 active particles enhance the performance of waterproof breathable fabrics by increasing the surface area and absorbing the energy your body produces to accelerate evaporation and breathability keeping you dry on the inside and allowing you to stay out longer. Billions of active micro porous 37.5 particles provide 800% the surface area to spread moisture