The StreemMaster Large Nozzle is carefully designed and manufactured to ensure it's super smooth and comfortable. The unique design has a safety ridge to ensure that the threads are away from your sensitive rectal skin while in use. As well, the internal part of the nozzle has been designed to control water velocity through all of the holes. You'll notice that water emerging from the five holes of the nozzle comes together to create a steady stream of water. Great care was taken during the manufacturing to ensure all the holes have very soft rounded edges. Nozzles are dishwasher ready, boilable, and easy to clean. Nozzle works with any standard shower hose. Black.