It's 3d printed out of engineering grade filled nylon 6 and nylon 12 filaments which allows it to have high strength along with amazing temperature resistance. 3d Printing allows you to make things in ways that are very difficult or expensive to do with traditional machining approaches or using off the shelf items.
This means you can add material where it's needed for strength, and don't have to have it in other locations where it just adds weight. By itself, the coil weighs only 6 ounces, and has a tensile strength of over 900lbs!
All the threads are done with high quality threaded brass inserts to allow high strength and repeated use without wearing out.
Why Stainless Steel, isn't it a poor conductor? Yes, yes it is, and the first versions were made out of tinned copper wire due to better conductivity and ease of fabrication. That was until one of my prototype units came back from 6mo on the Gulf Coast shoreline. Upon seeing the corrosion, it was switched to stainless.
Many revisions have been made of the coil in quality of the finished product, function, form, and usability. I feel that what is now offered is a high quality product at a fair price that won't disappoint.