FujiFilm WP-FXF500 Owner's Manual page 56

Maintenance
5
Coat the O-ring with the special grease.
6
Install the front-side O-ring (white).
O-ring (white) O-ring (white)
EN-24
To apply a uniformly thin layer of silicone
grease to the O-ring, squeeze out about
5 mm (0.2 in.) of the grease provided
with this product from the tube into a
clean plastic bag (about 10 cm (3.9 in.) ×
20 cm (7.9 in.) in size) and then knead it
thoroughly. Put the O-ring into the plastic
bag and continue kneading until the O-
ring is completely covered with grease.
The plastic bag can be used more than
once if kept clean.
For correct installation, observe the sticker
(white) inside the waterproof case.
Place the front-side O-ring on the
waterproof case beforehand to confirm
that the O-ring is not twisted.
If it is not twisted, make sure that it is
clean, with no foreign particles embedded
in it or dust stuck to it, before installing it.
If you cannot install the front-side O-ring
successfully, insert it into the four corners
first and then push the other parts into
the groove.