I have 3 set-ups
right now , or mix and match
they are the Blau "100mm"
cap , also sometimes called 110mm depending where you measure ,
3 styles of caps , Type A with the star tips on the edge , and Type2 without them and the 3rd is a stainless top on the cap ,
Blau caps from Europe , I have a couple of each style
and I have 2 steel collars / filler neck
one is 3/4 inch tall
the other 3/4 tall that has an internal ring , I have seen people mount a locking cap under the stock cap using the internal ring.....
plus a taller 2 1/2 inch aluminum filler neck
so a set of one cap , your choice and a collar / filler neck for $105
add $20 extra for the stainless cap including USA 48 state shipping
I am over by LAX airport if you wanted to pick it up