REDUCER HYDRANT 2-1/2"NSTx3/4". The product is a hydrant adapter, meaning it is perfect for connecting a hose to a hydrant. This model is made of brass and has the advantage of containing 2 pins for quick disconnect 4.5" and 1.5" high. Your pins are already included in the measure of its length. It is also the most common type of thread in use by firefighters today.