Feature: 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 Specification: Item Type: Check Valve Material: ABS, PVC Size: Approx. 16.5 x 11cm / 6.5 x 4.3in Weight: Approx. 439g / 15.5oz Caliber Specification: G1-1/2 (1.5inches) Use Place: Swimming Pool, Spa. Application Scope: It Can Be Used to Install the Water Supply and Drainage Pipes of Swimming Pools and Spas with Acidic or Alkaline Fluids at a Temperature of 5℃~50℃. the Check Valve Relies on the Liquidflow of the Liquid Itself to Automatically Open or Close the Sealing Baffle, Thereby Forming a Directional Liquidflow State of the Liquid. It is Mainly Suitable for the Water Outlet Pipe of the Machine Room Water Pump Installed in the Swimming Pool and Spa Pool, the Pipe from the Water Pump of the Integrated Filtering Equipment to the Filtering Equipment, the Automatic Drainage Pipe of the Filtering Equipment, Etc. The Main Function: A. Prevent Unpredictable Damage to the Pump Due to the Backflow of Liquid B. Prevent the Filter Equipment from Being Polluted Again Due to the Backflow of Liquid. Package List: 1 x Check Valve