These brass fittings are to suit 3/16 diameter (unless stated otherwise) copper or copper nickel brake pipe and are available with different male threads.
Automec Male Fitting For Brake Pipe - 3/8 UNF Short Type, Gold
Goodridge Straight Male Convex Seat Bulkhead Fitting - For -3 Hose 3/8 x 24 -3 JIC Thread In Stainless Steel, Silver
Goodridge Straight Male Concave Seat Fitting - For -3 Hose 3/8 x 24 -3 JIC Thread In Zinc Plated Steel, Silver
Goodridge Straight Male Convex Seat Fitting - For -3 Hose 3/8 x 24 -3 JIC Thread In Zinc Plated Steel, Silver
Moquip Straight Fitting For 100R6 Push On Hose - 8 JIC Thread For 1/2 Inch Bore Hose, Gold
Moquip 45 Degree Fitting For 100R6 Push On Hose - 5/8 BSP Thread For 5/8 Inch Bore Hose, Gold