This is a hypospray for Star Trek The Next Generation, modeled after the original design documents by Rick Sternbach. It was actually never produced in this form for the show (the neck is actually cylindrical for all the show props).
This discussion was very helpful in the design process:
http://discuss.fleetworkshop.org/t/sternbachs-hypospray-design-cad-model/1446
The model is scaled so 1 unit = 1 meter