English: "Zander Type A-12 Adjustable Weight Finger Joint Unit" is a cast-iron device that resembles a typing table. The center has a large U-shaped opening with a wooden hour-glass shaped armrest attached to the front of it, leaving half the armrest hanging over the edge of the table and half of the opening unblocked. A slender curved bar hangs over the space with a finger stall in the center of it. Its ends are attached to weights and gears on each end of the table top. The entire device is supported by two pairs of parallel iron bars, each attached to a cast-iron arc that forms a flat foot at each end that can be bolted securely to the floor. To use this device, the user rests the forearm and hand on the wooden surfaces and places a finger into the leather finger stall, which is set into a two-pronged iron fork. The finger can then be either flexed using the weighted lever on the right or extended using the one on the left, and the respective levers are weighted differently.