Olympus FL50 - Manual (Page 9)

EXCLUSIVE PRESSURE RELEASE PLUG
The body and lid are uniquely designed with a "no clip" closure arrangement. Our testing has shown that
this arrangement allows the water to exert an even pressure on the O-ring, thus increasing the reliability of
the watertight seal. To open the housing, the pressure release plug must be first unscrewed and then pulled
all the way out. This provides a channel for the air to pass though and eliminate the pressure differential
between the inside of the housing and the ambient air pressure.
The plug consists of an internal double O-ring seal on a stainless steel slide shaft. These internal O-rings
form the watertight seal. There is also a large outer O-ring under the knob. This O-ring serves to prevent
contamination [dirt or salt] of the slide shaft, and is not required for watertight integrity. If this O-ring
should become detached, it can simply be pushed back in place.
Important!
Before diving, make sure the pressure release plug is
pushed closed, and then screwed home, do not over tighten
this plug (finger tighten only).
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