The 2019 Mayhem makes Mountainsmith the first in the U.S. to launch a backpacking pack with Spectra® Fiber Technology. Spectra® Fiber is an ultralight, ultra-strong fiber that puts the Mayhem at the top of its class for weight and durability. The Mayhem 45 is ideal for backpacking weekends, backcountry huts, the local crag, and far away hostels.