Usage Tips:1、[Perspective Mirror Design] With a transparent mirror pipe, you can observe the internal movement, the check valve itself is anti corrosion and durable, easy to install. 2、[Long Service Life] Made of durable ABS and PVC, this water hose backflow preventer is sturdy and durable, with long service life, you can use it foe r a long time. 3、[Functional Usage] Prevent unpredictable damage to the pump due to the backflow of liquid, and prevent re contamination of the filter equipment due to the backflow of liquid. 4、[Widely Used] This check valve is mainly suitable for installation in swimming pools, the water outlet pipe of the water pump in the machine room of the spa. 5、[Wide Application] Also suitable for the pipeline from the water pump of the integrated filtration equipment to the filtration equipment, the automatic drainage pipeline of the filtration equipment, etc