It will work - but it would be more functional for homebrewing if it had a standard 1/2" NPT thread elbow on top and bottom - which is what I ended up piecing together. opening on top and bottom makes it easier to clean, and keeps it in place against the kettle/tun - and since I have all 1/2" npt ss parts lying around my brewery, it was much easier.
BUT, if you have the parts for this sight gauge, it'll work!
Works well but needs additional o-rings to not leak
Just a heads up. This sight gauge works great but I needed to add a #10 faucet o-ring (from Home Depot) after the elbow and before the nut and after the nut and before the washer in addition to the supplied o-ring. Mine leaked pretty consistently without them. No big deal but do this before you use this for the first time and you'll be glad you did.
This is getting 4 instead of 5 stars just because of that, otherwise, 5 stars.