At every knob and dial, underwater cameras have internal o-rings that seal out water. These o-rings wrap around the control shafts and are pressed into grooves called o-ring seats. Over the period of a year, these o-rings lose their elasticity and begin to flatten. As you turn your controls in water, these flat o-rings are more susceptible to water intrusion. Manufacturers recommend these o-rings to be replaced once a year. In our annual service, we install new factory o-rings. We then vacuum test and hydrostatically (in-water) test the camera to insure the highest quality of workmanship.