Part Numbers: XB4BG21, XB4BG21 Compatibility: Compatible with Schneider Electric Harmony XB4 Series Package Includes: 1x Key Switch Selector Assembly Installation: Direct replacement and easy to install. Delivers the same performance as the original. Benefits and features Key switch selector assembly for Harmony XB4 series control devices Provides secure key controlled operation in control panels Direct replacement with no modification required Exactly the same performance as the original component Specifications and fit Part numbers: XB4BG21, XB4BG21 Designed for Schneider Electric Harmony XB4 Series Use scenarios Replacing a worn or defective key switch in a Harmony XB4 based control panel Upgrading a control cabinet to restore secure key controlled operation Keeping a spare key switch assembly on hand for maintenance in manufacturing lines using XB4 components