Inverted Flare Union 3/16in Line 3/8-24 4pk

The Inverted Flare Union 3/16in Line 3/8-24 4pk is a precision brass adapter fitting designed for hydraulic and pneumatic systems requiring reliable fluid or air transfer between hardlines of matching diameter. This set of four inverted flare unions serves technicians, mechanics, and engineers who need dependable connections in high-pressure applications where leak-free performance is non-negotiable. Whether you're assembling brake lines, fuel systems, or custom hydraulic circuits, these fittings provide the secure, repeatable connections that professional-grade work demands.

Constructed from brass in its natural finish, each union features a dual 3/8-24 inverted flare female connection that accepts 3/16-inch hardline tubing on both sides, enabling straight-through coupling without dead ends or additional adapters. The inverted flare design—where the tubing end is flared outward and seated inside the fitting—creates a superior seal under pressure by maximizing contact area and reducing stress concentration at the fitting's critical junction. Brass material resists corrosion, maintains dimensional stability across temperature extremes, and delivers excellent machinability if field modifications become necessary. The compact form factor (3.5 x 0.6 x 4.55 inches) and lightweight construction (0.1 lbs per unit) make this four-pack easy to stock and deploy in any workspace.

Maintenance technicians, restoration shops, and OEM assembly operations benefit most from keeping multiple units on hand; the four-pack format reduces reorder frequency and ensures you never interrupt a project due to fitting shortage. Installation requires only a wrench or flare-nut tool and basic torque discipline—do not over-tighten, as inverted flare fittings rely on geometry rather than brute force for seal integrity. Compatible with any system using 3/8-24 inverted flare ports and 3/16-inch hardline tubing, these unions are ideal for vintage automotive brake systems, classic aircraft hydraulics, and custom-built industrial fluid circuits where modern push-to-connect fittings are neither available nor appropriate.