Total space for 10L of gear in the main compartment and in the two front zippered pockets. Reflectors and emergency whistle are there for added security. The straps for the shoulders, sternum and waist are adjustable for individual preference and Air bridge system in the back for easy carry. Hydration pack is constructed out of 600D Polyester and Honeycomb Dobby with water resistant coating. Comes with a 3L (H20)hydration bladder that is BPA-Free and FDA compliant. To organize the smaller items, there are mesh pockets, a key holder, and webbing attachments.