A ZUD 3/8 16 is a short female rod that ends in a 3/8 16 screw hole. It is primarily used to retrofit a Noga or Israeli arm (or similar) that ends in a 3/8 16 screw to a rod end so you can use a Zacuto quick release mount. It can also be used to mount an accessory that attaches with a male 3/8 16 screw. The ZUD tightens to your arm or accessory with a small Allen screw. The Zud is threaded on the inside so it can be extended with a Zacuto male rod of any length.