Lace up and head out in supreme comfort. For the men's Glycerin GTS 21, Brooks added 2mm more super-soft DNA LOFT v3 cushioning for extra plushness, while the innovative Guide Rails support system keeps you comfortably in stride. Plus, an updated, streamlined upper adds breathability. Features:. Supreme softness. Improved fit. Whole-body support. Specifications:. Designed for: Road. Midsole drop: 10mm. Weight: 10.5oz / 297.7g Specifications Terrain Road Width Normal Breathable Yes Drop 10 mm. Colour: black