Ambulance Parameter Extension (APE) kit M4758A, an accessory to the Philips HeartStart MRx Monitor/Defibrillator - Product Usage: is intended to be used with the M3536A MRx in EMS environments.
M4758A Ambulance Parameter Extension (APE) kit may cause ECG "Leads Off" condition in hot, humid environments
International distribution in the countries of Austria, Germany, Netherlands, Norway, Poland, Switzerland
https://www.accessdata.fda.gov/scripts/ires/index.cfm?Product=Z-1342-2020