PREPARATION-continued_______
The preceding instructions must be performed on each user-serviceable O-ring prior to each dive day and, if possible, prior to each dive . By following these pro - cedures and all other procedures in this instruction manual , you will be able to enjoy using your Nikonos 8peedlight 8B-102 for many years.
Reminder: An extra set of O-rings and a tube of lubri- cant are supplied with the flash unit. Additional O-rings and lubricant are available from authorized Nikon dealers and service centers.
The O-rings and their sealing method
The method used by the O-rings to seal and waterproof the flash unit is shown in the following illustrations. When a low level of pressure exists (for instance, just under the water 's surface), each O-ring seals its groove by its own elastic force (see Chart A). When the pres - sure increases (at greater depths), the O-ring 's shape is altered and its sealing ability is increased to withstand the greater pressure . The pressure changes the ring from its original "0 " shape (when looking at a cross - sectional view) to a '.D"' shape (see Chart B).
i Pressure
)y-
• Slight compression
O-rings
