PADI Open Water Scuba Diver Refresher Book, #70097 Diving Diver Lessons Course Authorized Dealer Full Warranty This is the PADI Scuba Tune-Up Guide Book. Brush up your skills with this easy to follow manual Review diving skills, equipment and safe diving techniques The SCUBA Tune-Up is perfect if you do not want to sit through an entire class again SCUBA Tune-Up is also useful just to have fun if you can't get out and practice on your own