What is a tether?
A tether is a strong strap that attaches on one end to the top of a car seat, and fastens on the other end to an anchor point behind the car’s seatback. It’s used to keep the top of the child seat from traveling too far forward in a collision. Not all child seats have tethers, but many infant seats do. A tether is an excellent supplement to the bottom LATCH connectors; it will keep the top of the seat properly positioned while the LATCH connectors secure the bottom.