The main difference is the regional availability of the two approval systems NRTL and CB scheme: Products tested by NRTL-certified laboratories are approved for the US and Canadian markets. The CB scheme, on the other hand, is a multilateral agreement that emerged from the European Commission for Conformity Testing of Electrical Equipment (CEE). Certified products may be traded in the markets of the member states of the International Commission on the Rules for the Approval of Electrical Equipment (IECEE). List of member states