The anti-rebound bar is for use with Canadian Britax ClickTight infant-child car seats (Marathon ClickTight, Boulevard ClickTight, and Advocate ClickTight). The anti-rebound bar is a separate component that should be attached to the front of the Britax infant-child car seat for rear-facing installations. The anti-rebound bar MUST be removed when the car seat is installed forward-facing. **Refer to your user guide for complete installation instructions. NOTE:Use of the anti-rebound bar is required in Canada. In the United States it is optional. In Canada the anti-rebound bar is included with the purchase of the seat. It is an accessory in the United States.