I was sure i got mine at mcmaster carr but could not find them in my order history.
They are 10-32 and i drilled and tapped my water jacket 10-32.Mine are white and i am pretty sure they are nylon.I found something else that works well also and better adjustability is the K&B brass water fitting and they are also 10-32 and perhaps only 45 degree but in the right application work well and do not strip as easily.I use them for water in ans water out on my 21 rigger withou an issue.