Du-Bro Threaded Couplers Part No: 212. Designed for use with Du-Bro Kwik-Links and ball links. One end has no threads and can be soldered on and the other side has either 2-56 or 2MM threads. This has 2-56 threads, threaded 3/4" \(19 mm\) with an overall 1 1/4" \(31.7 mm\) length. For .072" diameter rod.