How do I know if my child restraint is installed tightly enough?

The child restraint must not move more than 25 mm (1 in.) side-to-side or front-to-back at the belt path. If it moves more than this, the installation is not secure enough and you must tighten the lower anchor connector strap or vehicle seat belt, try again, or move the restraint to another location. Serious injury or death may result from poor installation. (Page 24–26)