Double layer washable merino wool, Underwoolies are a must-have cover for natural diapering.   These are soft and trim-the perfect under-garment cover-and work great as trainers.  Sloomb double layer knit Underwoolies are made from washable merino yarns, making them trim, breathable, soft, and comfortable–perfect for cloth diapered children from newborns to toddlers. Content: 100% merino wool extra fine easy care, elasticized waistband. Care: machine wash warm inside out (or hand wash), lanolize if using as a cloth diaper cover, lay flat to dry. Responsibly machine knit in China, oeko-tex certified wool yarns. Patent Pending 2015 size weight age size 0 5-12 lbs 0-4 mos size 1 10-18 lbs 2-12 mos size 2 18-37 lbs 12-24 mos size 3  30 lbs + 24 mos +  size 4 35 lbs + 36 mos +