These are machined fitting we make special for GMT-400 trucks & Suburban’s.
They allow you to hook to a 16mm x 1.5 supply side fitting. Has a female thread with a hose bump. (A hose bump tends not to tear the hose up like a barbed fitting does).
Allows you to run 1/2″ hose. also let you bush back down to a 16mm line (like in my Raptor BCD kit).