all the time.When do you use one?
red is 3.125, turquoise is 3.0625, something else is 3.00. most all of mine are bare aluminum, because i make my own, and there is too much spread between the colored ones.How do you know which color? and...
to fine tune the boat??why?
-generally-, stock cast nozzles are too large in diameter for the application, and they are not perfectly round. inserts are round. some people use a .125 and never change, others use different sizes as part of tuning.