Britax Safe N Sound Compaq MKII Instructions For Installation & Use page 45

ALTERNATIVE HEADREST ADJUSTMENT METHOD.
HOW TO ADJUST THE HEADREST & HASSLE FREE HARNESS™ -
Installed in vehicle
When the child restraint is installed in to the vehicle, the
headrest and shoulder strap slot height can be adjusted with
out removing the seatbelt from the restraint by using this
method.
A. Loosen the harness straps before adjusting the headrest.
B. Pull the top of the padded insert forward to expose the
"PUSH" label at the centre of the headrest
C. Place finger on the "PUSH" button, press in towards
restraint, lift the headrest loop to adjust upward or
downward.
Be sure to use the 'push' button label as a guide. Press the
'push' button (approx. 10mm) into the recess behind the
cover. Once released check the headrest has latched by
attempting to lift the headrest using the headrest loop.
Push
button
Instructions for Installation & Use
HOW TO USE
Headrest loop
45