$10 for a SWIVEL? Pass. In all the reading and videos I've consumed on the topic of spey casting - I have never, ever seen, heard, or read about anyone loosing a tip, head, or full spey line because of line twist. I haven't even heard of people complaining much of line knotting up and ****ing up a cast - and those that have said something admitted it was a line control issue. I may be wrong, but this smacks of some dude "innovating" solely to sucker people out of their money. $10 for a single swivel is retarded. The most I've ever paid was $5 for a pack of 20 premium swivels, 120lb ball bearing swivels, small enough to use with spinners on my trout rods. Remove the wire snap, and you have a much better swivel than what that dude is hocking, for way less cash.
Let me ask you this - do you want a metal swivel constantly going through your rod's guides when you're landing fish or casting? Seems to me something that can snag and cause a broken guide or broken rod. THAT would suck way worse than loosing a tip, or even a shooting head. Really, it looks like it's just braided mono that's been looped onto the swivel ends. I'd be worried more about it creating a funky hinge point and messing up casts. If you could find some braided mono, and the time to stop at Fisherman's Marine, you could make at least a dozen or more of those setups for what he's charging for one.