4"-inch f/8.6 OTA Construction - 4"-inch f/8.6 Dew Cap Fitting Rings 1
 

Rings used to attach the dew cap to the main tube... (Click for enlarged view)

 

Some of these aluminum tube rings are designed to help secure the dew cap to the outer objective  cell . The two rings  with the widest gap  will be inserted inside the OTA to help secure the ProtoStar flocking material on each end of the tube.