Manufacturer Part #: MT-501 Manufacturer: Multi-Tork SKU: 99-615-1006 - MT501 is a lightweight, poly-carbonate clamp knob socket designed for use on virtually any four-lobe industrial filter knob and Pentair's commercial in-line strainer lid model PS-2. Attach with any 3/8” drive ratchet or your portable drill and see the knob removed with ease.