XALD102 XALD102 Enclosed Push Button – NO Polycarbonate Green I. The Harmony Series is a range of push-button enclosures and pendant control stations that are used for direct control or auxiliary of processes and industrial machinery. This series is predominantly ideal for industrial, infrastructure and building applications and installations due to its wide choice of composition cut-outs. The Harmony Series range is all compatible to work with each other, interchangeably.