Top tethers can be found on all car seats made after Sept. 2002 that can be used forward-facing. This includes convertible car seats and combination car seats. On many car seats, the top tether is made to be used only in the forward-facing position. However, a few models allow for the use of the top tether in a rear-facing installation, so you should check your car seat owner's manual to see if this is an option for you.
The top tether attaches to a hook that is usually on the rear dash in sedans but often on the floor of a mini-van or in the back cargo area of an SUV. Any vehicle made in 2002 or later should come standard with LATCH, so check your car's owner manual for instructions. Some top tethers must be routed in specific ways over or under head rests, so it's important to check your vehicle owner's manual and your car seat instructions to be sure you're using the top tether correctly. For more information, check out "When to Use a Car Seat Top Tether."