Rare Wondrous Item (Navigator’s/Cartographer’s Tools), Requires Proficiency with Cartographer’s Tools or Navigator’s Tools, Requires Attunement 

When used as part of Cartographer’s Tools or Navigator’s Tools, it gives a +1 bonus on ability checks made with them. This feature doesn’t require attunement to the item. 

Once per long rest while holding the Spy’s Spyglass, you can use your action to look through it, outlining for you the silhouettes of all non-invisible creatures within 60 feet of you for 1 minute.

This ability allows you to even see the silhouette of creatures through walls or obstacles, making you able to discern their creature size, general shape, and their distance from you.

Once per long rest as an action, you can activate the eavesdropping mode of the spyglass for 10 minutes. While this mode is active and you are looking at a creature through the spyglass, you begin to hear everything the creature hears as well, including whatever they are saying themselves for as long as you are looking at them during the duration.

This feature works if you see any part of the creature or of what it is wearing, no matter how small.