The SM1A9 thread-to-thread adapter contains an internal SM1 (1.035"-40) thread and an external C-Mount (1.00"-32) thread. Made of anodized aluminum, it is machined with the two threads connected by a flange and can be placed at the end of a threaded tube. It is typically used to make a camera lens from an SM1 lens tube. The unpackaged weight of this adapter is 2.95 g.