How to shower or take a bath with your cast First, choose the right SEAL-TIGHT protective cover for you. SEAL-TIGHT comes in a full range of adult and pediatric sizes to waterproof casts on the arm or leg of any family member. Choose the SEAL-TIGHT ORIGINAL model—it’s guaranteed to last the life of the cast. Simply slip your leg or arm through the rubber diaphragm and into the latex-free, watertight covering. Then, turn on the water, and that’s it! SEAL-TIGHT keeps your cast dry during your bath or shower the easy way. You avoid dealing with annoying tape, straps, pumps or homemade solutions that may leak.