TOSOKU Rotary Mode Select Switch DPP02-2-21H20 13.5° step, 25 position

According to data sheet from manufacturer:

this rotary switch is 

With the small screws the starting and end positions can be adjusted. 

DP-series 
with waterproof adapter (the aluminum disc with double sided tape)
Code Type: Complimentary Binary Code 

Step angle: 38.5 degree

Length of shaft: 20mm

What’s the difference between DPP and DPN?
DPP has the waterproof adapter (the aluminum disc with double sided tape)