Hagstone (Patreon)

Not too big on coins, eh? Well how about rocks... everyone loves rocks...this one has a hole in it?

The shop keep passes you a rather lumpy rock with a metallic lined hole in the middle. Around it are marked notches... it doesn't take a genius to work out something here is missing.

DM notes – think view finder. The two disks fit in either side and can be rotated to fit into the notches. Have it as a way to see into different material planes once they have the lenses or a way to see into the future or past... go nuts.