The Vac Lock is a safety mechanism designed with a spring action cover that secures the pool cleaner hose in place and automatically closes the suction fitting when not in use. It is compatible with all suction pool cleaners, including Pool Vac, Navigator, Kreepy Krauly, and other similar models. Installation instructions: 1. Apply silicone sealant to the 1 1/2 inch male threads and hand tighten into the 1 1/2 inch female thread wall fitting already installed in the pool. This fitting connects to the suction side of the plumbing system and should include a 3- or ball valve at the equipment for flow rate adjustment. 2. Screw into the wall fitting as far as possible with the "marking" facing upward, ensuring the spring is on top. 3. Secure the set screw. 4. Use a screwdriver to open the flap and insert the vacuum or pool cleaner hose. The internal clip will help hold the hose in place when the pump is off. 5. When not in use, ensure the cover flap is securely snapped closed. 6. Never operate a pool or spa with an uncovered suction outlet or vacuum port. Color: White Material: Plastic Package Contents: 2 x Vac Locks Note: Light reflection and differences in display screens may cause slight variations between the color shown in the image and the actual product. Measurement may vary by +/- 1-3 cm.