We have used them to check the temp of wet concrete at the surface when we have problems finishing in the winter. All it tells us is if in a few months the top might pop off. Oh yes, it happens.
This is the one I got. I cant really use it on the grill. I sometimes use it to tell the the the differnces in temp on the steel on my pit in different areas.To get some idea on temp diffence. It is some thing I could live with out but I still like to mess with it every now and then. I did not buy it for bbq my dad got it when we had lizards. I think it goes up to 700