This is the Padi eLearning ReActivate Refresh Book For Scuba Diving Student Features:Learn How to: Assemble a scuba unit Handle common problems Perform basic skills with ease Why ReActivate? Your PADI certification never expires; but if you haven&';t been diving in a while, it&';s better to be over-prepared than risk a problem because you forget something important. Dive shops also appreciate seeing a recent ReActivated date on your certification card.