A short 15mm rod with female 1/2"-13 thread inside and ¼-20 screw hole on the other end.
It is primarily used to retrofit an arm (or similar) that ends in a ¼ 20 screw to a rod end. It can also be used to mount an accessory that attaches with a male ¼ 20 screw. It tightens to your arm or accessory with a small Allen screw.
The 15mm rod with 1/2"-13 thread inside fits Zacuto male rod of any length.
The short 15mm rod seems very versatile and could be used in many scenarios. It could be attached to articulating arm via 1/4"-20 threaded hole, and it could be mounted with Microphone shock mount for microphone. It could be operated with a hex spanner for convenience and features light weight. That's awesome!