Supreme Softness: Compared to the Glycerin 20, the Glycerin 21 features 2mm more super-soft, nitrogen-infused DNA LOFT v3 cushioning to maximizie softness.
Improved Fit: New, engineered warp knit upper is breathable and alllows for a flexible, accommodating fit while staying soft against your foot.
Smooth, Stable Transitions: The broad platform stabilizes your foot and promotes smooth heel-to-toe transitions.