Side inlet dust collection filter bags are 24" in diameter and will fit neatly over the top of 55-gallon drums. Side inlet design allows heavy particles to fall directly into drum and airborne dust to collect on singed inner surface of bag. Air passes through the shaker-felt fabric at 40 CFM per square foot of fabric. Free technical assistance is available. American Fabric Filter P.O. Box 7560 Wesley Chapel, FL, 33545