The Eames constantly made use of new materials. The couple's first plywood chair - the Eames Lounge Chair Wood (LCW)-made use of a heavy rubber washer glued to the backrest of the chair and screwed to the lumbar support. These washers, which have come to be called 'shock mounts', allow the backrest to flex slightly.
This technology was brought back in the 670 Lounge chair. The backrest and headrest are screwed together by a pair of aluminum supports. This unit is suspended on the seat via two connection points in the armrests. The armrests are screwed to shock mounts on the interior of the backrest shell, allowing the backrest and headrest to flex when the chair is in use.
This is part of the chair's unusual design, as well as one of its biggest flaws. The rubber washers are solidly glued to the plywood shells, but have been known to tear free when excessive weight is applied, or when the rubber becomes old and brittle.