Salt water dial hydrometer, useful for beer?

I've been trying to get a better precision hydrometer for my final gravities. The refractometer works great for OG but even with the calculations it doesn't agree with my hydrometers after fermentation is done. I also bought the unbreakable plastic hydrometer, but it seems to be off by 5 points in distilled water. Anyway I found the pictured hydrometer on ebay and I think it may be a good way to get FG readings accurately



http://cgi.ebay.com/Instant-Ocean-A...emQQptZLH_DefaultDomain_0?hash=item1c0c89eb3f

Now that's a nifty idea, I'm interested to see how well it works.

Accurate to +/-.001 for ten bucks? Wow, seems hard to go wrong. Maybe you're on to something entirely new here. Give it a try!

Seems like a good idea, see them at Petco or Amazon for a little less green. For $10 I would certainly give it a shot.

Don't bother. I have an aquarium and the swing arm type hydrometers are notoriously inaccurate. I think you are wasting your money.