Justrite vertical drum polyethylene pop-up gauge is a low cost solution to overfilling drums during waste disposal operations. When drum is almost full, indicator "pops-up" to warn you. Horizontal Drum Cast Iron Fill Gauge allows you to easily check liquid level of a horizontal drum at a glance - no more surprise re-orders or stock depletions. Use indoors or out, wherever you need to monitor the liquid level of drum contents. Sight gauge shows how much liquid remains in a 30- or 55 gallons drum. Drum gauge installs easily by threading into a standard 3/4-inches NPT bung hole and accepts any 3/4-inches faucet. Rugged zinc plated, cast iron body stands up to heavy use. Heavy gauge glass tubing is protected with a chrome plated housing and permits use with non-viscous oils. Buna-N seals make this unit ideal for petroleum products.