On my bike I have a Topeak MTX Quicktrack 2.0 rail system. This is useful for the Topeak panier bags that I don't use. Occasionally I test radio payloads by using my bike to ride some distance away from a receiver. I wanted to have a way of building a payload on my desk, then quickly connecting it to my bike without much hassle. So I remixed two other 3d models into my own 2020 MTX Quicktrack sled thing. Haven't ridden it in anger, but I'm pretty confident it'll go well in the real world. Pretty happy with how its come out. Radiosonde for scale https://www.printables.com/model/1886524-2020-topeak-mtx-quicktrack-20-sled