The glycerin 13 pushes the limits of 3d fit print technology to create a newly enhanced seamless upper for streamlined support the new dynamic saddle wraps the foot in secure comfort and the updated wraparound collar adds the finishing touch for a perfect blend of ideal fit and plush comfort the upper features a conformable saddle that wraps the foot while 3d fit print creates a custom fit without adding weight at just 109 ounces the glycerin 12 is lighter than ever but full of new techn