A perfect compliment to your F1 Mainframe™, or J34 Just One™ pack. Increase capacity of any of these systems by zipping in either size dry bag for a lightweight load hauler. The roll-top lets you compress your load down and the taped seams keeps your gear dry.

Combine the J2DB/J3DB with a pair of Batwing Pouches™ to make a lightweight, capable, meat-hauling day pack.