Dennie, the roving electrician, has a long career of blowing out backpacks. With his hefty cargo of clipboard, laptop, miscellaneous tools, cell phone and lunch bag, it doesn't take long before he's ripped off a strap, split a seam, or busted right through the bottom of standard bags. For him and tradesmen like him, we've created a backpack that's built big and brawny enough for the long haul. We've crafted it of our heaviest 13-oz. Fire Hose cotton canvas treated with FendOff™ to repel water and stains, and finished it with full-grain 100% cowhide leather trim and grab handle.