The SB342 is made of durable, reinforced nylon and features plastic panels throughout the bag giving it a semi rigid construction. The attachment system is hook and loop for fast installs although you will probably need to make use of a couple of the external tie points to get the bag highway secure. Luckily, tie points are plentiful with a total of 14 around the perimeter of the bag... The 342 comes with quite a few extras. There are two adjustable straps that are perfect for securing items to the outside of the bag, a complementary waterproof cover, and a removable shoulder strap for easy carrying. The main compartment is quite large and you can access your items from three sides using one of the zippered openings. Below the main compartment, on the front, are two adjustable straps for securing even more to the outside of the bag. The SB342 has four additional compartments on the exterior; two on the left side of the bag and two on the right. All four of these compartments are expandable, by about an inch, by unzipping these zippers 360 degrees. Opening the main compartment front zipper exposes a hidden mesh zipper pocket in the lid and the plastic reinforcement.