Air pump hose adapter

I needed an adapter for my portable air pump (a cheap Vastar bought on amazon but can be found on aliexpress as well) so i designed one: The adapter final diameter is 5.5 mm (0.21 inches) while the thread is large 7.4mm (0.29 inches) and it should fit most of the other pumps (tried with another chinese one from a friend) Hope this might help someone   Happy Printing