06 FAB - 06 (3/8) H x 06 (3/4-20) FAB, Swivel, 338P Weatherhead Fitting
 
This fitting's thread is "female air brake", also known as "ball seat" they require an adapter to be used for installation to convert to NPT. 
3/8 MNPT:Part number:1390x6x6
 
Danfoss's 338P series hose ends are DOT compliant compatible with the EC038 series hoses. They are manufactured using CA360 brass and specifically designed for air brake lines.
 
Danfoss has a full range of braided and spiral hydraulic hoses to meet the requirements of all low, medium and high-pressure hydraulic applications. Whether you need high-performance hoses for critical systems or standard hoses for others, our complete portfolio has you covered.