Isofix is a child car seat attachment system which uses metal anchor points built into the chassis of the car. The Isofix connectors on your child car seat fit on to these. The anchor points are often hidden within the car’s seat padding. On some car seats, the Isofix connectors are part of the seat itself. With others, you have to buy a separate Isofix base to install into your car, and your seat will click on to this. Once the connectors are clicked together with these anchorage points, a baby car seat has to be secured by a third point. This can either be a support leg, which comes built into the seat or seat base, or a top tether (a strap that attaches to a mount somewhere behind the rear seat). Both of these work to prevent the car seat tipping forward in an accident. You can find Isofix on baby car seats (Group 0+. I-Size), toddler car seats (Group 1, i-Size) and Group 2/3 child car seats.