Womens Base Rib Tank Colbolt Refund Request ParkChicago. Crafted from soft stretch baby rib, this slim scoop tank is designed for a close, flattering fit. Finished with slim self fabric binding and a classic scoop neckline, its an easy, everyday layering essential. Crafted from 92% cotton 8% span stretch rib. Round neckline. Designed to be close fitting. Go up a size for a more relaxed fit. Please note all sale purchases are final.