What you need for the five AOW dives depends on what the five dives are; only Deep and Nav are mandatory. Nav requires a compass, and a slate. The AOW crew-Pak comes with the slate. You do not need to own either but you probably should. For Deep, the student must have a light (because it might be dark at depth) and a slate (to write down info and questions). Again, you do not need to own either, but you should have a light. Other popular dives for the three electives are Night (requires a light, a backup light, a tank light, and a compass); Peak Performance Buoyancy (nothing special needed); Wreck (you need a slatemaybe a light, and might need a reel, depending on what your instructor decides to cover); Search and Recovery (compass, possibly a light, slate, reel, lift bag, rope, depending on your instructor); Boat (SMB or DSMB, compass depending on conditions). There are many possibilities for the three elective dives, and most of them have some kind of equipment requirement. But purchase of the additional equipment is not a PADI requirement, even though a particular shop or instructor says that.