Both the single and double bridle bit has a look funktion 

Both the single and double bridle bit has a look function  
Currently there are two ring options:
1.   Loose / ordinary ring  
2 .  D ring 

Is there difference between what types of rings you should use when you ride?
The answer is yes!
The D ring, under riding, will have support at the cheek, where as the Loose Ring will  move in the first part of the mouth (because it is loose) and will therefore not have the support like the D ring.  

There will come other versions of ring types in the future.  To see what is planned, look under futures versions