The Flame King 20LB propane cylinder comes with an overflow protection device valve & a built-in gauge. Never again will you have to worry about running out of propane with the built-in gas meter gauge that provides accurate gas level readings. This tank is pre-purged vacuum ready for filling of propane avoiding you the cost and headache of purging your new tank. It is built from high grade welded steel and powder coated for rust prevention. For your safety, your tank comes with an OPD valve to prevent overfilling as well as x-ray and hydrostatic tested. You can be sure to transport safely both in the US and CA as they are DOT and Transport Canada certified.