What is LATCH and how does it work with the Graco car seat?

LATCH (Lower Anchors and Tether for Children) consists of lower anchors and top tether anchors built into your vehicle, and connecting hooks built into the car seat. Lower anchors are used INSTEAD of the vehicle's seat belt to secure the car seat, while top tethers are used IN ADDITION to lower anchors or the vehicle's seat belt for forward-facing installations. All 2003 and newer model year vehicles are required to have LATCH. The car seat should not be installed with LATCH when the child weighs more than 45 lbs (20 kg) with the internal harnesses. (Pages 45-46)