GPS

Informational accessories work from your inventory or your void bag. Leave it in the bag and keep the real slots for things that change your numbers. The only argument for equipping it is if you want a modifier on it, which is rarely worth the space.

Depth tells you which layer you are standing in, and that decides what spawns around you and what you can pull out of the water. Horizontal position tells you how far you are from the ocean and roughly where the dungeon and jungle sit relative to spawn, which matters when you are digging blind. In multiplayer anyone on your team standing near you reads it too, so one person carrying it covers the group.

This was the first combined information accessory, well ahead of the others, and it later became part of the handheld that merges all of them. Building it is never wasted work.