Those things are way too expensive to loan out, and you can't sharpen them. Well, maybe you can, but I can't. Mine are tucked away in a dark, secret place. That sounds weirder than it actually is.Many years ago I had a set of left hand drill bits. That is to drill into the metal the drill had to be set on reverse. Great for drilling out broken bolts.
Also great fun when someone asked to borrow a drill bit...