Hocosa Organic Merino Wool Baby Shirt, Long Sleeves, Envelope Neckline. Made of soothingly soft European KbT-Certified Organic Merino Wool. Natural fibers breathe, maintaining a comfortable temperature in warmth or cold. Even when damp, wool feels warm, unlike cotton & synthetics. Naturally flame-retardant, without chemicals, making it perfect as infant sleepwear. Natural wool with lanolin gives self-cleansing properties, minimizing need for washing. For best results, wash occasionally by hand with lanolin-replenishing woolwash to maintain hygienic effects. For best fit - European size correlates to full length in centimeters. (Baby's length in inches x 2.5). For For chunkier babies, choose next size up. See Product Description below for more sizeing guidelines.