Another part to add to the kit! A “simple” large-bore pneumatic pinch valve. I’m kinda maxed on face count with the two end pieces gasket and two-part body. I could make the body a single face, but being able to vary texturing a little between the two halves does add a bit of variation, so you can make the bottom half rusty  (rustier?), or the top part painted in warning stripes…

Or use smaller pipes with it and pretend it’s some kind of boiler?

Things like that.