The double D shaft can be swapped out for shorter or longer shafts. Comes standard with a 3 3/4″ shaft length that will give you 4 3/4″ overall length.
I do have some dedicated size arms left over from a special order. These are 15mm & 19mm arms. They only will work with that size iris rod. They are laser etched for the size they are dedicated too. They will not fit three sizes of iris rods just the one size! While supplies last! Will not be made again. Anodized “Black”