Mercedes-Benz 350 SDL Owner's Manual page 40

SUPPLEMENTAL RESTRAINT
SYSTEM (SRS)
38
Emergency Tensioning Retractor
(ETR)
The seat belts for the front seats are
equipped with emergency tensioning
retractors. These tensioning retractors
are located in each belt's inertia reel
and become operationally ready with
the key in steering lock position 1 or 2.
The emergency tensioning retractors
are designed to activate only when
the seat belts are fastened during
major frontal impacts within the
shaded area shown. They tighten the
belts in such a way that they fit more
snugly against the body restricting its
forward movement as much as
possible.
In cases of less severe frontal im­
pacts, roll-overs, certain side impacts,
rear collisions, or other accidents
without major frontal forces, the
emergency tensioning retractors will
not be activated. The driver and
passengers will then be protected by
the fastened seat belts and inertia reel
in the usual manner.
For seat belt and emergency tension­
ing retractor safety guidelines, see
page 42.