Although the hood thermometer on my Weber Genesis II E-310 is good quality and relatively accurate, it does not give an accurate reading down at the grill plate level. I purchased this ambient probe because I use my grill for low n slow smoking of Briskets and for Pork Butt Roasts. This requires that the burners on one side of the grill remain off. I clipped this ambient probe to the grill plate just an inch from the meat and I was surprised to see that when it reached the 275F mark the hood thermometer was showing a temp of 350F. That's a HUGE difference when your smoking low n slow. If you have an iGrill then this probe is a must.