We sometimes get asked about suction head choice on our bridge mount dry fire hydrants. In general, we prefer using a male suction head with polymer cap because the head is stored in a "facing up" position to prevent condensation forming ice in colder weather. The two photos showing a female head in this news story were taken in December 2020 in the mid-Atlantic area and show just a small build-up of ice from condensation in the female swivel after just a couple nights of cold temperatures. Generally not a big but it can be if folks don't check and maintain their DFH connection....especially in cold weather climates.
Ice formation from condensation can sometimes prove problematic when using female suction heads on dry fire hydrants.
The male suction head faces up and is covered with a threaded cap, thus the chance of ice build-up from condensation is minimal.