Blending two of Mystery Ranchs most crucial design breakthroughs the 3-ZIP and OVERLOAD features the TERRAFRAME 50 3-ZIP is for mountain zealots who need the option of going light or going big. Weve offered the OVERLOAD feature in hunting and military packs for years, yet backcountry climbers, fisherman, guides, and others have been asking for a mountain-inspired version of this versatile, load-taming design. Featuring rigid, carbon fiber frame stays, the suspension allows an ideal amount of torsional flex while providing ample support for loads up to 150 lbs. This functional expandability, the OVERLOAD, is your secret weapon when carrying awkward, excessive loads.