If you're using the Lower Anchors you MUST use the tether for a forwardfacing install. If you install with a seatbelt it is optional though STRONGLY recommended (the use of the tether when ffing reduces head excursion in a collision). If you are installing rearfacing (whether with the lower anchors or the belt), the tether is optional. Yes, Britax recommends its use but it is not required for a rearfacing installation.
7/30/07 at 7:29pm