I also have one as a spare prop, although mine is a 4 blade jobbie.
Yes they are made by Piranha, and appear to work very well.
Although I've only tried it briefly and it is the same pitch as my Stainless one.
My reasoning was that it was lighter to carry around as a spare than another Stainless or Ali one. If you are carrying a spare make sure you also have a spare Washer, split pin and nut with you of course.
Oh and it was less than £40 on ebay with two spare blades. It was advertised as an old Johnson one, and with JWs help I knew I could put it in my lathe and take 5mm off the back of the outer lip to make it fit my Suzi.