For standard rotary switch/potentiometer shafts passing through panel cutouts or housings. Units seal both shaft and panel-out. Silicone rubber is tolerant to sunlight, weather, salt-spray, ozone, most acids and cleaning solvents. Units RFI suffix are EMI shielded. Meet MIL-B-5423. UL recognized. CSA certified. This rotary shaft seals are molded from a high tear-strength siliconee rubber bonded to a built-in mounting nut. Each seal surrounds the rotary shaft and forms a watertight and dust-tight seal against the shaft and front panel surface.