I don't know that I'd want to order anything from a place that advertised that Xinc could make the fly sink like it's lead. Our resident chemist explained it right that all these products do (and I use them) is make the surface film easier to penetrate. When you squirt Dawn in greasy pan you're running hot water in and see that slick shoot out from where you shoot the Dawn you're seeing what is basically a water lubricant. We'd add a shot or two of Dawn to a cement truck to make it easier to work with as long as inspectors weren't doing slump or strength tests on that load.

I have a cyber friend who sells both floatant and sinkant (?) and when people were asking about how good his product was I wrote that the first time I used them I accidentally tipped the Sink bottle and my boat was going down rapidly. Scrambling I dumped his Floatant on the spill just in time to bring the boat back to level before it swamped. Now that's good stuff.