The CW threaded, splash proof, IP67 sealed bushing for T and T1 actuators has a standard internal O-ring. An external bushing seal washer is available separately from APM Hexseal. The part number is MFS-60064. The external bushing seal is placed on the switch. The switch is then inserted into the panel and the mounting nut is applied. Once installed, the switch is IP67 sealed above the panel. They are designed to be used in Shut-off switches and Small equipment applications.