Material: Rubber. Built for frequent use and designed to maintain a stable seal over time. Function: Seals the connection between fill valves and the water supply or internal components of the fill valves. Ensures a tight seal to prevent leaks, supports proper valve operation, and helps avoid water waste. Performance: Reduces noise from water flow and improves overall tank efficiency. Contributes to a more durable and efficient toilet system. Maintenance: A good seal minimizes leaks or damage, reducing maintenance requirements, costs, and frequency. Compatibility and size: Designed to fit standard fill valve connections in most toilets. Sized to accommodate common valve assemblies and configurations. Use scenarios: Residential toilet : a worn seal to stop a slow leak at the fill valve and restore efficiency. Commercial restroom upgrade: install during fill valve replacements to reduce water waste and operational noise. installation: include with a toilet to ensure a reliable, leak connection between the fill valve and water supply.