Well I made a 3D model of one of the parts and had a friend 3D print it with PLA. I will run it and see how it holds up over a season. They could be injection molded from Acetal, but 1000 units is the standard minimum with any outfits around here. The unit cost to cover the mold making would still be quite low, but I am not sure I could ever sell 1000 of these for 5 bucks each.