Prospex diver PADI watch is composed completely of stainless steel. In 2016, Seiko released a limited-edition Prospex PADI to commemorate the company's cooperation with the Professional Association of Diving Instructors. The automatic calibre 4R36 is used in this new limited edition Prospex model, which is a re-edition of the Seiko Pepsi 6309 model from the 1970s. This watch is sealed to be extremely waterproof.
