Carhartt B01 Double Knee Duck Pants. Made in the USA, these are original items from the American-made era. The B01 is Carhartt's most classic and authentic workwear model, and the fabric, stitching, and overall feel are different from the current overseas-made products. The thick brown duck fabric has acquired fading, wear marks, and soiling from years of use, resulting in a unique, one-of-a-kind look derived from real work. The double-knee reinforcement and the rugged straight silhouette of the Original Fit represent the completed form of workwear at the time. They possess a convincing quality that cannot be replicated by fashion-oriented reproductions or processed items.