Hi guys, In my car i do not have an ISOFIX system. Its strange as i'm sure it is a free upgrade. Anyway, I contacted Mercedes dealers who said they do not have a retrofit kit. I questioned them and after a bit of digging around i managed to find the part number for the kit. outer left anchor A2118600187 outer right anchor A2118600287 inner left anchor A2118600387 inner right anchor A2118600487 bolts N0000003853 pop rivet for anchors A0009915532 Also found a link to help install the anchors. Mercedes-Benz W211 E-Class Isofix retrofit Hope this helps rather than searching multiple links.