MATERIAL: 420 Nylon outer shell. The collapsing duffel easily holds a full set of gear and keeps your costly regulator and computers protected. The large mesh duffel zips into the end of the padded regulator bag creating a compact, easily stowed container. 29Â? down to 4Â? 420 Nylon outer shell and Nylon reinforced mesh. The padded reg compartment is designed to match the shape of the Pro Regulator Bag (AKB601). YKK #5 zipper. DETAILS: Padded regulator compartment. Same shape as AKB601.