The Brooks Glycerin 21 provides you with miles and miles of softness and comfort. This plush shoe is optimized for your comfort by being lightweight, responsive, durable and cushioned. Whether you are on your feet all day for work, enjoying a daily walk or training for a marathon, the Brooks Glycerin 21 transforms your experience, making the pavement feel softer and smoother as you put in the work. One reviewer in our Brooks Glycerin 21 review, describe the experience as "running in this shoe reminds me of jumping on a bed, with the same fun factor involved. It was plush and comfortable with just a bit of bounce back." Details Upper - A new, engineered warp knit upper improves the fit and feel on your foot. It is breathable and flexible, while still being soft and secure. Midsole - the new nitrogen-infused DNA LOFT v3 is added to the Glycerin and there is even more of it to give you a plush, durable and responsive ride. A broad platform makes sure you have smooth heel-to-toe transitions. Outsole - New RoadTrack rubber on the outsole is lightweight, durable and includes recycled silica.