This part of ISO 1135 specifies requirements for single use transfusion gravity sets for medical use in order to ensure their compatibility with containers for blood and blood components as well as with intravenous equipment. Secondary aims of this part of ISO 1135 are to provide guidance on specifications relating to the quality and performance of materials used in transfusion sets, to present designations for transfusion set components, and to ensure the compatibility of sets with a range of cellular and plasma blood components. In some countries, the national pharmacopoeia or other national regulations are legally binding and take precedence over this part of ISO 1135. This standard differs from DIN EN ISO 1135-4:2012-06 as follows: a) the scope has been restricted to gravity feed applications and the whole document aligned accordingly; transfusion sets for single use used in conjunction with pressure infusion apparatus are now dealt with in Part 5 of the standards series; b) 3.3 "Designation" has been deleted; c) Clause 8 "Labelling" has been restructured to bring it into line with the current specifications of the European Commission; d) normative references and the Bibliography have been updated; e) the European Annex ZA has been updated and brought in line with the current specifications of the European Commission; f) finally, some minor editorial changes have been made in the entire document. European Standard EN ISO 1135-4 has been prepared by Technical Committee ISO/TC 76 "Transfusion, infusion and injection, and blood processing equipment for medical and pharmaceutical use", in collaboration with Technical Committee CEN/TC 205 "Non-active medical devices" (secretariat: DIN) with the participation of German experts. The responsible German standardization committee is Working Committee NA 063-02-02 AA "Transfusions-/Infusionsbehältnisse und -geräte aus Kunststoffen" ("Transfusion/infusion containers and equipment made from plastics") at the DIN Standards Committee Medicine (NAMed).