This Reima merino base layer set combines warm merino wool on the outside with soft, non-itchy lyocell on the inside for reliable thermal control during play and sleep. Designed as kids’ thermal underwear and long johns, this two-piece thermal set keeps children warm even when wet while staying breathable and gentle on sensitive skin. Soft, flat seams prevent chafing and the elastic waist provides a secure, flexible fit for active days and cozy nights. All-over Moomin print adds playful style to this sleepwear and base layer, and the premium composition (48% merino wool, 43% lyocell, 9% polyamide) delivers lasting warmth and durability.