This pack was specifically designed to be a climbing daypack, but functions so well for everyday use that it has become my most used pack. It is a reconfiguration of the utility bag I used to wear all the time. It expands quite a lot, but gets small for use as a bookbag. It is completely waterproof, not just water-resistant. With this bag, if closed correctly, you can go swimming and expect to have a dry towel at the end of the day. This is accomplished with an independant waterproof lining tucked between the interior and exterior fabrics. There is a zipper on the inside so that you can check on the waterproof liner, patch holes, or re-seal the seams. The interior fabric is bright yellow so you can see inside. The exterior panels which expect to see a lot of abuse are lightweight, but reasonably durable fabrics. The closure is similar to a dry-bag, and rolls down tightly to clip into a three-way buckle. The shoulder straps are comfortable with moderate loads, and dont soak up sweat. Reflective accents on the back and shoulder straps keep me safe at night on a bike. The back panel is padded with closed cell foam, and lined with athletic mesh. This makes the bag comfortable to wear when it is hot, unlike a non-breathable exterior like just about every other pack out there. Elastic fills out the package, offering a place to tuck a fleece in, clip extra gear, and keeps the contents compressed so they don't swing when biking and climbing. The inside also has a velcro patch to attach a modular pocket, and a key clip. There are also numerous extra attachment points to configure appropriate compression and strap systems as befits the situation. The color scheme is based on the predominant hues found in Red Rocks National Park, in Nevada, where I spent spring break hundreds of feet off the ground wearing this pretty thing.