These self-closing covers provide an easy and inexpensive way to convert steel drums into fire-safe receptacles. A replaceable fusible link assembly inside the cover melts at 165 deg F automatically slamming the cover shut if there's a fire in the drum. Covers are made of steel with a chemically resistant powder coat paint finish. Fits drums from 22-1/2" - 22 3/4" in diameter. FM Approved