Cotton Duck Bib Overalls Unlined bib overalls are designed for durability and comfort. Heavyweight Carhartt® brown cotton duck is water repellent, and overalls are strengthened with metal rivets at vital stress points. The double knees feature cleanout bottoms, and the back pockets are reinforced. The high back with elastic suspenders ensure a good fit, and various utility pockets keep important items close at hand. Re-treat after washing to retain water repellent feature.