The Air Necklace is an upgrade available to Knuckles the Echidna in Sonic Adventure 2. It gives him an unlimited supply of air while underwater. While not required for anything, it makes Knuckles life significantly easier in levels with lots of water, particularly Aquatic Mine and Cannon's Core.
- Purpose: Allows Knuckles to breathe underwater.
- Location: Aquatic Mine. Set the water level to No. 3 first. Go down into the underwater brick room. Take the dash panel that lead to a room with many wooden 2-by-4s. Dive down deeper and you will find another brick room with a narrow vertical tunnel. Begin to surface there and you should find the Air Necklace. Be sure to move fast as you could run out of air.
- Requirements: None, except that the Shovel Claw is incidentally needed to get to this point in the story.
- Required For: Nothing. The player was meant to have this before tackling the 3rd or final missions of Death Chamber, but it's possible to do without. Nothing in Aquatic Mine or Cannon's Core was designed to require this item, but it was meant to aid significantly in those levels nonetheless.
- Equivalent: None.