Maintenance of o-rings on Paralenz+

This part is straightforward. 

The only o-rings that need maintenance are the three ones located under the end cap. 

There are more o-rings in the camera (e.g., around the lens or inside the end cap) - you should not touch these. 

The most important thing to pay attention to is that the o-rings are always shiny, clean (with no debris, hair, or dust on!), and have no scratches or breaks. 

If the o-rings look dry, you should put a thin layer of o-ring grease on. You can use your finger, tissue, or brush to do so.

Please note that putting too much grease on the o-rings might cause the camera to flood.