A NPC that hosts 55x2. You use the item on the gambling NPC and guess if the dice rolls over 55 or under 55. If you choose correctly, your bet will be doubled. E.g. I bet 1 elysian spirit shield - i guess it correct - i get paid out with 2 elysian spirit shields. If you use a noted stack, the NPC asks how many you would like to bet. E.g. I have 300 dragon scimitars noted in my inventory - i use it on the NPC, it asks me if i want to bet between 1-300. Cash can also work like this.

Bear in mind that its a personal choice if you want to bet or not. I look forward to hearing you responses.

The NPC could be 'Party Pete'.