Support & product information — updated 27 August 2026
123Hand is a LiDAR photogrammetry instrument for measuring the volume of a human hand. It is used by armwrestlers, coaches and researchers who want a repeatable, non-contact alternative to water displacement. You tap once on each side of the wrist, move the phone through 34 guided capture positions around the hand, and the phone reconstructs a 3D mesh, cuts it at the wrist plane and reports the enclosed volume in cm³. Scans are grouped by subject so volume can be tracked over time. 123Hand is not a medical device and makes no health claims.
An iPhone with a LiDAR scanner — iPhone 12 Pro / 12 Pro Max or any later Pro / Pro Max model — running iOS 17 or later. iPad and non-Pro iPhones are not supported; on those devices the app shows an explanation screen instead of the scanner. The full-detail reconstruction is an optional offline process on a Mac and is not required to use the app.
123Hand uses an email-and-password account so a subject's scan history follows you between phones. The account stores only the subject name you typed, the scan date, your device model and the measurement numbers. Capture photos, depth maps and meshes stay in the app's folder on your iPhone (visible in the Files app) and are never uploaded. There is no third-party sign-in, no advertising and no tracking.
To delete a scan, open the subject and swipe left on the scan's row. To delete your account, tap the account icon in the top-right corner of the home screen, choose Delete account and confirm with your password. The account and every scan record stored under it are removed from our servers immediately. Files still on the phone can be removed in the Files app or by deleting the app.
Email [email protected]. Include your device model and iOS version if the question is about a scan.