1+ Flagstaff  
2+ Flagstaff base  
3+ Flagstaff boss  
4+ Rubber seal  
5+ Base  
6+ Fixing plate  
7+ Rubber seal  
8+ Base  
9+ Plate  
10+ Knurled blanking knob  

The part numbers in the assembly image below relate to the product number in the table. Clicking on the part number will open up the relevant part details.