TefenNylon 66 Hose Fitting, 90 Degree Elbow, Gray, 5/16" Hose ID (Pack of 10),12256505003

works good for my application (repair of my fuel line)

I use this for my blow-off tube on my fermenters (if they had a 3/8 x 3/8, that would have worked too, but I didn't see one.) The 3/8 side fits perfectly into the bung/pail grommet of the fermenter, and the 1/2" side fits perfectly into a 1/2" vinyl or silicone blow off tube that goes down into a jug half full of Starsan. It's nice and short compared to sticking a tube onto the center port of a three piece bubbler. Once active fermentation is done, you can put your standard "S" type or 3-piece bubbler back into your fermenter.

I really like these. Well built and look exactly as pictured in the ad. Excellent value for the price.

This will work perfect. I intend to build a model old fashion Grist Mill with a water wheel and the elbow is part of my water delivery system and should work well.

Great. as expected.