Carhartt's classic duck active jacket is designated by the model number J130.
The J130 refers to Carhartt's insulated Active Jac made with washed or sandstone duck fabric. Its familiar workwear design combines a full-zip front, attached hood, rib-knit cuffs and waistband, multiple pockets, and a roomy cut that allows workers to layer clothing underneath.
Carhartt's model codes distinguish closely related jackets. The J140, for example, is the firm-duck version of the insulated Active Jac, while the J130 is associated with the softer, pre-washed sandstone or washed-duck construction. That similarity is the main source of confusion between the two numbers.
Carhartt has described newer products as updates to the popular J130, and current listings may use a different commercial product number, such as 104050, while still identifying the design lineage. Thus, J130 is the canonical answer for the classic jacket model asked about here.