JVC WR-MG88U Handbuch Seite 4

O-ring
Rubber ring for waterproofing.
Check to ensure that the ring is not twisted and foreign materials are not
attached, followed by attaching it to the designated position.
O-ring
Swab
For cleaning the O-ring groove.
Press it lightly against the O-ring groove and move it around the circumference
of the groove.
4
Swab
Dirt, sand, salt
crystals, etc.
Hair, thread, etc.