The Glycerin 23 continues Brooks' tradition of premium cushioning in their flagship daily trainer. DNA TUNED foam delivers a noticeably soft, smooth ride that keeps your legs feeling fresh through long runs and high mileage weeks, while a refined upper provides a secure, comfortable fit from the first mile to the last. If you want a daily trainer that feels as good on mile 20 as it does on mile 1, the Glycerin 23 is it.