This part of ISO 29061 provides criteria for the judgement of usability of child restraint systems (CRS) with ISOFIX attachments and their corresponding anchorages in the vehicle. This part of ISO 29061 provides criteria for a separate evaluation of the child restraint ISOFIX attachments, of the ISOFIX anchorage installation in the vehicle, and an evaluation of the interface issues when installing a child restraint system in a certain vehicle. This part of ISO 29061 covers both rigid and flexible attachment systems of the CRS. NOTE Although ISOFIX is defined in the original “ISOFIX” standard (ISO 13216-1) to be a rigid system, the term “ISOFIX” in this part of ISO 29061 is extended to include flexible CRS attachments (LATCH, UAS).