Features [Perspective Mirror Design] Features a transparent mirror pipe that allows observation of internal movement. The check valve is corrosion-resistant, durable, and easy to install. [Long Service Life] Constructed from high-quality ABS and PVC materials, this water hose backflow preventer is sturdy and built to last, offering extended service life. [Functional Usage] Helps prevent pump damage caused by liquid backflow and avoids recontamination of filter equipment due to reverse liquid flow. [Widely Used] Ideal for installation in swimming pools and spa machine room water pump outlet lines. [Wide Application] Suitable for use in pipelines from water pumps of integrated filtration systems to filtration equipment, as well as automatic drainage lines of filtration systems. Specification Item Type: Check Valve Material: ABS, PVC Size: Approx. 16.5 x 11 cm / 6.5 x 4.3 in Weight: Approx. 439 g / 15.5 oz Caliber Specification: G1-1/2 (1.5 inches) Use Place: Swimming Pool, Spa Application Scope: Designed for use in water supply and drainage pipes of swimming pools and spas handling acidic or alkaline fluids within a temperature range of 5–50°C. The check valve operates by relying on the liquid flow to automatically open or close the sealing baffle, ensuring a unidirectional flow state. Main Functions: A. Prevents unexpected pump damage due to liquid backflow B. Prevents recontamination of filter equipment caused by liquid backflow Package List 1 x Check Valve