Usually, this kind of products can be used on the equipments in order to reduce the noise and filtering the dusty or the air or oil or water and so on.by the way, our product has three kinds of thread including BSPP(G) ,NPT and BSPT. or if you want some of them be nipple or zinc plated, that's OK,Our products mainly used in many large equipments, and be used for refuse the dusty,oil,air,and anyother materials which can't be work with the equipments at the same time, to reduce the noise is other function