The ArkivA(R) Side Zip compartment is made from the same Ultra and EPX fabrics as our NASA pack and works perfectly for adding more capacity and organization to the core design. The weatherproof side zips are ideal for transporting longer items like narrower water bottles. The MW X C Mars Project Arkiv accessories come equipped with four custom logo orange Arkiv Clips and features dual direction YKK Aquaguard zippers for added water resistance. As with all Arkiv accessories, the side zip can easily be removed and used as an external organizer.Each NASA Arkiv pack is equipped to hold two side accessories and one front accessory. Made in the USA Measures (External) : 14.5" x 5" x 2.75"Measures (Internal) : 11" x 4.5" x 2.5"Weight: 0.5 lbs