We did our homework. The results are in the bag. Our ClassMate backpacks are better than ever. The chest strap is back, taking pressure off kids' shoulders and keeping postures strong. We also reinforced the grab handle, added best-in-class YKK zippers and sturdy mesh pockets designed to hold water bottles in backpacks of every size. What hasn't changed? The lightweight yet tough fabric that keeps our backpacks going for years, plus personalization options that make each one as unique as the child who carries it. All dimensions are approximate; Small: 16"H x 11.5"W x 6"D; Sized for shorter tikes or little ones just starting school, it's best for kids 3'6" - 4' Medium:;17”H x 12”W x 7”D; Sized for younger elementary school kids, it’s best for kids 4’ and over Large:;18”H x 12.5”W x 9”D; Sized for taller/older elementary school kids, it’s best for kids 4’3” and over XL:;19"H x 12.5"W x 10"D; Sized for middle schoolers and older, it's best for kids 4'6" and over