DIVER'S SUPPLY is a store that specializes in providing equipment and supplies for scuba diving and other water sports. It offers a wide range of products, from wetsuits and fins to tanks and regulators. AIR is the three-letter solution to this crossword, which refers to the AIR tanks used by divers to breathe underwater. These tanks are filled with compressed AIR and provide divers with a safe and reliable source of oxygen while they explore the depths of the ocean.