This is a #6 shutter, with pin assembly for "instantaneous" exposure (1/25 if it is to be believed). 3 1/2" opening, 6 1/2" outside dimensions. New, old stock, in box, with instructions and pin assembly. I have taken it apart, cleaned and checked it. No hose or bulb. Pictures on demand. $100 delivered CONUS, more elsewhere. Satisfaction guaranteed.