A tether is the most important part of a forward facing car seat – but not all vehicles have the anchors to connect the tether to. Tether anchors (for forward-facing car seats) are standard in all cars, trucks, vans & SUVs in the US since model year 2001 – but those with vehicles model year 2000 or older that do not have tether anchors typically CAN RETROFIT a tether anchor (often quite easily and inexpensively).