Made of GOTS-certified, 100% organic cotton. 2-way chrome/lead/nickel-free zipper opens from neck to ankle for easy dressing...and also from ankle to neck for easy diaper changing. Zipper safety tab cover at neck and tiny zipper "pocket" at ankle for extra safety. Fold-over, mitt-sleeves (in sizes preemie/nb to 6/9m) for added warmth and protection from self-scratching *Please note that babies need sensory exploration and tactile stimulation every day, so be sure to leave little hands uncovered for a portion of the day :-) Rubber-dotted grip soles on all sizes to prevent slipping. Thoughtfully designed with soft elastic on back of ankles for a stay-in-place fit. Tagless for added comfort against baby's skin. Azo-free, non-toxic, eco-friendly dyes.