Make life easier when you use liquid propane gas for appliances in your camper, RV, boat, or home. The LP Gas Checker tells you in just a few seconds how full-or empty-a propane tank is. Easy to carry or store is about the size of a writing pen and weighs less than an ounce. For all commonly available steel and aluminum liquid propane tanks with a diameter of 8 to 14 in (203 to 356 mm). WILL NOT WORK ON TANKS WITH A CENTER WELD.