API 6A flanged spacer spool adapter
Double Studded Adapter Flange (DSAF) or Double Studded Adapter (DSA) is a flange with a through bore and a ring groove on each side, drilled and tapped bolt hole sets on both sides and tapped end studs complete with nuts fitted on both sides. Unlike a spacer, the two sides are usually different in size and/or pressure rating. Double studded adapter flanges are commonly utilised to connect and adapt flanges with different nominal sizes, pressure ratings, and configurations.
 
API Spec 16A drilling spool Main technology parameters（flanged spacer spool adapter）1, Working pressure3000~15000psi (21~70MPa)2, Nominal bore7 1/16~13 5/8 (179.4~346.1mm)3, H2S Trim.4, the ring grooves flanges are all lined with the corrosion resistant alloy
5,   According to the latest API Spec 16A standard,and quality standard of ISO9001.