adrenaline bernoulli bolt 2 0 o ring kitAs indicated on the image, the smaller size 14 O ring replaces the one on the front of the bolt and the larger size 16 O ring replaces the middle O ring. On the rear of the bolt there are two O rings which are size by side and the size 16 replaces the forward one. When complete these two side by side O rings should now be the exact same size.