Sorry for bump, but how does this work anyways?
When you are building something, you might have to set multiple bricks to the same properties. For example, you might want to make a series of bricks to be a Rocket L. spawn, but also turn their rendering off. Most people will select "copy" on those fields, and then proceed to wrenching each brick and clicking send.
However, with the auto wrench, those fields with "copy" checked off automatically are applied to the brick! No need to press send, which speeds up the process a good amount.