Did salmon on my griddle in the 380. Used the surface temp gauge and found it to be accurate. i wanted 400* and set control for 400*. Got 406* on the control actual and 400+- on the surface gauge. Did not want too hot for the salmon. Result was perfect although finished product not shown. Was more interested in testing the temp gauge. Although I have to open the pit to read, it allows me to move the gauge anywhere on the surface.  Worth the purchase.

Looks like a great temperature gauge!

Looks like a great temperature gauge!

Seems to be OK on first cook. For $12 what could go wrong?  It is slow to get to there but I've got time. Supposed to be water proof but says don't put in dishwasher. Only seal is around the glass on top, otherwise one piece. With a max of 600* it should be useful when I need to know surface temp. Nice to be able to move it around or remove when desired. Just use my tongs.  Disclaimer: I admit that a good chef adjusts technique to get to the best possible result no matter if grill temps are not desirable. But the whole idea of PID controls is Set it and forget it, even tho that is not always the result! Onward and upward!