I've no idea whether this design is widely available (this one is from China), or to a different specification. It concerns me that the spring wire material is aluminium. So it may not be as durable as steel wire. But it does seem that the design could have merit and yet I wonder what drawbacks there may be? Perhaps imply too much stress on the spring? I imagine this can't be the first time the design has been made and sold and yet I don't recall seeing anything like it before. It's striking to me for it's simplicity and even a certain elegance, compared to one or two of the designs I've seen mentioned here previously.
Who is up for making one in their workshop?
Would titanium wire be any good?