Good stuff; well worth trying.
No, this is not for dry flies, at least not this diameter. From the extreme end of the tippet spectrum, 21.6kg or 47.6lb is very strong stuff. Thing is, if I round up a group of monofilaments the same diameter, 0.50mm, then this is exceptionally strong. For example, the editor's favourite Maxima 0.50mm lists a breaking strength of 12.5kg, one of my favourite leader materials Stroft ABR 0.5mm is listed at 21kg. I cannot find many freshwater tippets this thickness, compare saltwater materials and again this is exceptionally strong for the stated diameter.
Gigafish don't exactly state what their mono is made from, they do make it clear this is not fluorocarbon, that it is less dense than fluorocarbon. Very slick, reasonably supple for this diameter, simple knots seem to tighten well and stayed secure.
I'd use this for tarpon, then again I know salmon anglers who use stuff this thickness for salmon. I'd also guess they might baulk at the idea of tying 47lb leader to their lines.
Thing is, I can get the strength I want and have a thinner leader – which should equates to more movement, more action in my fly. Good stuff; well worth trying.
Note: Comparing tippet materials objectively is not easy, the diameters are not always accurate, breaking strengths can be measured in several ways, all of which are difficult for laymen anglers to reproduce. So, the trade body for the tackle trade in Europe, EFFTA, came up with their Line Charter, www.efttalinecharter.com, compliant manufacturers then print the EFFTA logo on their spools. It would be great to see that logo next time I handle a Gigafish spool.
Price: £10.45 per 100m spool.