This part of ISO 22241 specifies the refilling interface for the NOx reduction agent AUS 32 in compliance with ISO 22241-1, which is needed to operate converters with a selective catalytic reduction (SCR) exhaust treatment system. This part of ISO 22241 specifies the minimum functional and geometric requirements of an open refilling system, in order to ensure compatibility between the on-board refilling system and the off-board refilling system. Compatibility conditions for a sealed refilling system are provided in Annex A. This part of ISO 22241 applies to commercial vehicles and buses as defined in ISO 3833 and having a gross vehicle mass of more than 3,5 t, designed to use stationary off-board refilling systems. This part of ISO 22241 also applies to the nozzle of stationary off-board refilling systems. NOTE Throughout this part of ISO 22241, the term “NOx reduction agent AUS 32” is abbreviated as “AUS 32”.