Replacement locking knob CX900G or knob kit CX900DA for pool cartridge filters and separation tanks. Designed as a direct replacement for Hayward Star Clear Plus Cartridge Filter and Separation Tank models C751 C900 C9002 C1200 C12002 C12002S. Key benefits Restores secure lid retention so the filter tank closes and holds correctly during operation. Solves common issues caused by cracked, stripped, or missing knobs without changing the filter assembly. Directfit design reduces installation time and avoids modifications to the tank or lid. Available as a single replacement knob CX900G or as the CX900DA knob kit for a more complete option. What it does and why you need it Function: locks and holds the filter lid in place to maintain proper alignment and reliable operation of the cartridge filter system. Compatibility: fits specified Hayward Star Clear Plus Cartridge Filter and Separation Tank models C751 C900 C9002 C1200 C12002 C12002S for a fit with those systems. Fit and size: manufactured to match original part dimensions so it replaces the factory knob without adaptors or adjustments. Durability and performance: made to withstand normal pool service conditions to provide dependable locking action over repeated use. Practical attributes Model options: CX900G locking knob or CX900DA knob kit depending on replacement needs. Installation: simple swap with the original part; installs in place of the worn component for immediate use. Maintenance: ideal for routine filter maintenance and for restoring proper tank closure after wear or damage. Use scenarios Seasonal maintenance: a worn or brittle knob before the start of pool season to ensure the filter lid secures properly during regular operation. Post restoration: after servicing the cartridge or replacing the tank lid, install the CX900DA knob kit to complete the and restore original fit. Onsite emergency fix: quickly a stripped or broken knob that prevents the lid from locking, allowing the system to to service without delay. What to expect A direct replacement option tailored for the listed filter and tank models that restores locking function and fit. Choice of single knob or kit to match the scope of the . Note Confirm compatibility with your filter or tank model numbers C751 C900 C9002 C1200 C12002 C12002S before ordering to ensure correct fit.