Etymotic DI-15® High-Definition Electronic Earplugs for Dentists - Manual (Page 8)

Operation
8
ON/OFF
The DI-15 is on when the switch is closest to the device.
The DI-15 is off when the switch is out. Note: It is not
necessary to remove the battery as long as the switch is
in the off position.
Automatic Protection
• No interference with natural hearing; soft and loud sounds
are heard naturally
• Automatically delivers 15-dB protection when
steady-state noise exceeds safe exposure limits
• Impact noise protection
Adaptive Noise Reduction
The circuitry in DI-15 earplugs automatically changes output
levels as sound input levels change. Hearing is natural, as
if nothing is in the ears, until sound reaches unsafe levels.
As environmental sounds exceed safe limits, DI-15 earplugs
reduce sound to safer levels. Natural hearing is restored
when sound returns to safe levels.
OFF: Switch OUT
ON = Switch in
OFF = Switch out
ON: Switch IN