The ultra-miniature M3 threaded quick-disconnect assembly is designed to connect lines of pneumatic systems, providing quick, positive, and leak-proof connection in an extremely small envelop. It is suitable for applications where small package size, leak-tightness, durability, and light weight are required. The M3 is comprised of a brass (or stainless steel) internal end and a stainless steel external end. The entire assembly weighs 3.4 g. The internal end, designated QM3I, is designed with an automatic shutoff valve and an M3 internal thread. The internal end is only about 16.7 mm long and has a 6mm hexagonal body. The external end, designated QM3E-M3E, is designed with a M3 external thread and includes a captured O-ring seal. The performance and ultra-miniature size of the assembly make it easier for users to miniature products.