The WE-FLEX series provides functional isolation with a withstand voltage of 500 V_RMS. For higher isolation test voltages, a customer can use the WE-FLEX HV series which provides an isolation test voltage up to 1.5 kV_RMS. In order to provide basic insulation instead of functional insulation, the pinout for the types EFD15 and EFD20 are different. Another difference between the WE-FLEX and WE-FLEX HV is the use of metal clips to provide an even pick-and-place surface. The WE-FLEX HV transformers provide up to 15% higher saturation currents than their counterparts.