This is just for fun please nothing too dirty or inappropriate. Lets say you have a utility belt (batmans utility belt for example) what would you have on it or in it? Best answer goes to most creative with most detail.
Honestly, the kryponite shard came in handy the most for batman, so I'd go with that. Honestly, out of the Pantheon of Heroes and Villains, almost everyone is affected by kryptonite, though humans need prolonged exposure to get cancer. But, I remember one story where Superman is shot by a kryptonian bullet, and batman saves him by using either the kryptonite shard, or a scalpel he made from it, I can't remember which.