Criteria 4 reads:
"Each shipment is sent under a valid contract between the exporter and the importing facility, requiring the importing facility to complete all applicable requirements in paragraph 26b. The exporter shall perform regular on-going due diligence to ensure importing facility(s) and any other third parties involved are consistently meeting the requirements of paragraph 26b"
From p. 11 of Basel Secretariat. 2014. ‘Draft Technical Guidelines on Transboundary Movements of Electronic and Electrical Waste and Used Electrical and Electronic Equipment, in Particular Regarding the Distinction between Waste and Non-Waste under the Basel Convention (Draft of 20 November 2014)’.