these go between the tap and the kettle.
1/2 inch npt female so you can screw the tap into the other end.
they are weldless so you just drill a hole and insert. you can put a thermometer in the other end also but since my aio has thermometer and i figure it already has the hole for the tap . i can just insert this in between . im going to try it and see how it goes.
i was worried also about liquid not boiling but read several threads about kettle sight glass users and thats not an issue apparently the liquid is either boiling in the tube or near boiling.
was wondfering if anyone else has already doen this,
i think the 16 inch should fit
thanks for the replies