REI Co-Op Mountainmaker Pants - Toddlers - Boys 4T - New without tags. Never worn. - Color is grey, called “Castlerock” - Has adjustable elastic waistband. - UPF 50+ sun protection. - 94% nylon, 6% spandex. - Smoke free home and ready to ship! From family day hikes to getting the hang of riding a bike, the toddlers' REI Co-op Mountainmaker pants have the fit and fortitude to handle the demands of an active tyke.