This model was created to solve a very specific problem for my Immortan Joe costume. The screen-accurate gas mask hose that connects from the air bladder behind his head to his mask is actually a combination of two different types of hose. The light grey hose is from a PDF-D childrens' gas mask and is more flexible, which was probably done on purpose to make it easier for the actor to move his head about. The black hose is the more standard type of russian gas mask hose you frequently find on the Soviet GP-5 or M41M masks. These hoses, stock, actually screwed together without any problem when I bought them, but the connection point on them was way too big like that. Instead, what I opted to do was design this piece to replace the connectors entirely. Slide the grey hose up over the smaller diameter end, and the black hose over the sleeve on the larger diameter end, and ta-da!
This item is not meant to be anything more than cosmetic. I've noticed I actually get a good airtight seal on my own printed copies, but these should not be used for any practical applications with an actual gas mask.