Here’s one from way, way, way back in the day. You’d find the Vaughn Automatic Arm developer advertised in STRENGTH magazine and Bernarr MacFadden’s Physical Culture magazine throughout the 1920’s. An interesting concept for sure, you started out with the weight positioned at the beginning of the rod and moved it farther and farther away as you got stronger. In other words, the resistance increased as your mechanical advantage decreased. There was plenty of torque so whether intentional or unintentional, something that this device did extremely well was to turn every movement performed with it into a grip and forearm exercise.