You're buying a wrench. The checkout clerk disappears in a cloud of sulfur and reappears as a demon. She tells you she will sell you the wrench, but if it's eve

You're buying a wrench. The checkout clerk disappears in a cloud of sulfur and reappears as a demon. She tells you she will sell you the wrench, but if it's ever used for evil, your soul will be bound to her for eternity. She then holds up a virtually identical wrench and says "this one is fine, though, do whatever you want with it." You really just need it to tighten some fittings under your sink. Which wrench do you buy?