You are bidding on a pair of torque arms, right side and left side, designed specifically for the 2021 TerraTrike Rambler with 24" wheels. These torque arms should work with other years of the Rambler, and even other steel frame TerraTrike models that have the same dropouts. A buyer confirmed that these torque arms perfectly fit their 2019 TerraTrike Rambler with 20" wheels, and a TerraTrike Gran Tourismo.
I have designed these in CAD software for my own rear hub electric conversion project, but had several more copies laser cut from 4.7mm thick (0.187") 304 stainless steel plate. Each one weighs 1.1 ounces.
These torque arms are designed for an electric hub motor that has a 12mm diameter axle that is notched on the sides to 10mm width. These torque arms are cut to very high tolerances and fit very tight, so they could be used for regenerative braking without wobbling.
The torque arms are unfinished, so you can either paint them, polish them to a mirror finish (what I have done on my trike), or just leave them as is. They are stainless steel after all.