APC AP4424 Automatic Transfer Switch Rack PDU 230V 32A Dual Input ATS – Fully Tested & Working. APC AP4424 Automatic Transfer Switch (ATS) Rack PDU in good working condition. Unit has been fully tested and is 100% functional. Fully Tested & Working. Dual Input Automatic Transfer Switch (ATS). 230V / 32A Power Distribution Unit. Pulled from Working Environment.