The grill gauge works great on 20lb. propane cans.The problem is I did not see a mention on the site it is ONLY FOR 20lb. propane cans. It will not weigh a 30lb. propane can. My problem is all our pro... Show More.pane cans are the bigger cans. It weighs the bigger cans at half full when they are empty. So, for me it is usless,but I do have one 20lb. propane can the gauge can be use on.