Pentax EPK-i Owner's Manual page 16

6
Insert the air/water supply plug of the water bottle
into the air/water supply connector of the scope.
7
2
Attach the suction tube of the suction unit to the suction nipple of the scope.
Be sure to use sterile water for the water bottle, and replace the water everyday.
Be careful not to turn the water bottle upside down, or squeeze it. Doing so may result in water flowing out of the bottle.
Make sure the scope is inserted slowly and correctly.
Do not hold the scope locking lever when you move the processor.
16
Preparation
Air/Water Supply Connector
Air/Water Supply Plug