Halcyon wet notes are an essential component of every diver’s pocket contents.
In the wet notes, you can record tasks to complete on the dive, backup decompression schedules, or if you're a cave diver, your navigation plan.
The pouch also becomes your underwater tool kit, with a lot of cave divers carrying a SS Shifting spanner, O-ring pick, selection of O-rings and a few cable ties in it. This way if something fails all the way down at the water's edge, you don't have to unkit and walk or climb all the way back up to the car to repair it.
If you're becoming a tech diver or a cave diver, this is an essential item.