Graco NAUTILUS SNUGLOCK LX Instruction Manual page 43

17A. Tighten Top Tether Strap
Remove all the slack.
18A. Test For Tightness
Grab the sides of the seat where the UAS
strap is and slide the car seat side-to-side
and front-to-back.
If the seat moves less than 2.5 cm (1"), it is
tight enough.
See section 5-A to secure your child.
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