FISON inspired lens hood for Industar (and Elmar?)

I love the classic Leica accessories but i am not willing to pay 60 to 80 € for an original FISON lens hood for my Industar 22 lens. What i wanted to design was a classic lens hood, that protects the lens and obstructs the viewfinder as less as possible.

PS:My version of FISON is longer than the original but I have not yet checked if the tube is too long. Should you find that it is visible on the edges of the negative, just inform me and i will create a shorter version.