Child's Arm Holder Supervised by Medical Professionals Regular Price: ¥2,860 Waterproof Cast Cover Regular Price: ¥1,680 Set Sale Please see the description in the images for product details. Used when I fractured my elbow. The arm holder didn't cause any shoulder or neck pain, and I was able to use it without stress. There are many similar types of waterproof casts, and I was hesitant when purchasing, but I was able to use it without any water getting in, even when moving around or soaking in the bathtub.