The 221551-3 is a BNC jack-jack adapter designed for 50 ohm RF coaxial connector applications. It features a nickel-plated brass body with a gold-plated beryllium copper center contact and PTFE dielectric material, providing excellent electrical performance and corrosion resistance. The adapter measures 32.54 mm (1.281 inches) in length and is styled as a Type A configuration, enabling quick and reliable interconnection between two BNC female connectors. This adapter is fully intermateable with comparable UG/U connectors and is commonly used in RF test equipment, telecommunications systems, and laboratory instrumentation where low VSWR and stable impedance matching are required.