NWT Allbirds Natural Run Form Tank, Small, Gray The Women's Natural Run Form Tank is medium support fitted tank with a built-in self bra —made with a mix of eucalyptus and wool to dry quickly. Break a sweat, not the planet with this medium support, fitted tank with a built-in shelf bra. Made with a mix of sustainable materials like eucalyptus tree fibre and merino wool, it wicks moisture, dries quickly and keeps you cool for every squat, stretch, and stride. Use: Running, training, walking Material: 43% Tencel™ Lyocell, 30% Recycled Nylon, 18% ZQ Merino Wool, 9% Elastane Fitted, hits at waist Compressive, midweight fabric Questions: Please comment below. Please review all photos. Smoke/Pet Free Home.