The Series 9004 Straight Male BSPP x Male Metric hydraulic adapters, made from carbon steel, are designed to connect British Standard Pipe Parallel (BSPP) fittings with metric fittings in fluid power systems. BSPP connections are similar to NPSM but differ in thread pitch, requiring thread sealant for secure sealing, which happens through a metal-to-metal or metal-to-metal with O-ring seal. The female swivel BSPP seals on the male connector's cone seat, providing a reliable connection. BSPT fittings, which are tapered, share some characteristics but are not interchangeable with BSPP due to their different sealing methods. Metric adapters conform to international standards such as ISO 9974, ISO 6149, and DIN 7631, with their threads resembling BSPP, though caution must be exercised as they can be difficult to differentiate. Metric fittings often have a 30° chamfer on the male thread, similar to BSPP, but variations in sealing surfaces and thread sizes can make identification challenging. To measure metric threads, a caliper can be used to determine the outer diameter in millimeters.