Eaton Weatherhead 1/4″ NPT Male x 1/4″ JIC Male
Eaton Weatherhead C5205X4X4 Carbon Steel SAE 37 Degree (JIC) Flare-Twin Fitting, Adapter, 1/4″ NPT Male x 1/4″ JIC Male
More InfoFrom the product description, check product page for current description, price and availability:
- Adapter fitting for joining a pipe to a tube in a range of fluid transfer applications
- 1/4″ male NPT threads on one end and 7/16-20 male JIC threads on the other for use with 1/4″ OD tubes
- Zinc-plated 12L14 carbon steel for strength, durability, and resistance to corrosion
- Operating temperature range of -65 to +400 degrees F (-53 to +204 degrees C)
- Meets SAE 070102 specifications for tube fittings
This fitting could be used for a lot of things including, potentially, putting together a Spunding Valve Build. 
A Spunding Valve allows you to ferment under pressure, naturally and precisely carbonate in the keg, fix over-carbonated beers and more.
See: [Build a Spunding Valve]. Take a look at Build Option 2 for a version that uses a similar although not identical fitting.
Eaton Weatherhead C5205X4X4 Carbon Steel SAE 37 Degree (JIC) Flare-Twin Fitting, Adapter, 1/4″ NPT Male x 1/4″ JIC Male – note that multiple variations of this product may be available, as such a different version may appear at this link
Make sure the components you use are compatible and rated for your intended application. Contact manufacturer with questions about suitability or a specific application. Always read and follow manufacturer directions.