With the nearly constant refinement of bike parts and pieces, we've entered into an era of very lightweight components and frames. While this makes for easier rides up the mountains and more comfort out on the flats, the increasing importance of respecting manufacturer's torque specs makes an accurate torque wrench, like the Effetto Mariposa Giustaforza II, almost a necessity. Effetto Mariposa is named after the butterfly effect, and in bike terms, suppose that you or a hamfisted mechanic makes a tiny error while torquing a fastener on your bike. And perhaps more likely than the butterfly flapping its wings in Brazil and creating a tornado in Texas, that one mis-torqued bolt could lead to a chain of failures and potential disaster on the bike. Independent tests at the Interbike trade show with passerby's and volunteers show beyond doubt that human hands are not torque wrenches. And no matter what any mechanic says about their ability to