JanSport Tahoma Pro Series Alpine Performance Backpack with GridFit GridFit harness plate for on the fly torso length and shoulder width adjustments to conform to the shoulders; adjusts easily when adding clothing or changing terrain Top-loading extendable hood easily converts to daypack for the final summit push or afternoon stroll from camp to the creek S-Curve, dual density shoulder straps with unbound edges to eliminate hot spots and rubbing Lightweight, removable BladeFrame suspension system with ergonomically molded composite sheet and 6061 aluminum stays for efficient weight transfer to the hips and lightweight strength, providing maximum comfort for long days with and heavy loads Innovative VX07 Sailcloth fabric is extremely strong, rugged and lightweight, and naturally features 1/4 inch rip-stop; a torn sail doesn't work so well at sea, so JanSport innovated the use of this ideal fabric for our Pro Series packs as well