I installed it on a T with my site glass. Brewed for the first time with it yesterday. Problem was that it wasn't long enough to pass through the T and into the kettle. Even with recirculating, my temps were reading 10-15 degrees behind the rest of the kettle as I was heating.
I will probably have a 1/4 inch half coupling welded on so I can get better readings directly in the kettle. Having it on the output might work better too as long as I'm recirculating.