Pff, this thing is a boon. A standard adjustable wrench is pretty handy if you have the right technique, but every once in a while you need to put more torque through one than they like to handle.

My dad sent me one of these a couple of months ago, and within a few weeks it totally justified its existence, allowing me to remove an incredibly tight spindle from a 600 pedal when otherwise I'd have been completely stuck - the flats I had to grip were only a couple of mm wide and I can't imagine any other tool not mashing the crap out of them.

And the security of the locking fit means you can leave your open end/ring spanners to gather dust until you can't access the fastener with one of these.

Also really handy for using as a handle with cassette lockring or BB tools and such; clip the clamp and they're one.

I'd like to give that Knipex thing a try too; that looks like a tool I've wanted to exist for a long time.