Long : The transducer discs with premium material, anti-aging, anti-, can last a long to 5000hrs. Compatable with: the replacement discs diameter is 20mm, as the optimyst parts, it fit for electric heater. Application: If your optimyst fire lack of mist or stop mist, the transducer disc may help to solve the problem. Replacement transducers disc for optimyst fire If your Opti- fire had stopped misting, it possible problem as the transducer. Try to replace the transducer disc, it may help your electric fire smoke effect come back. Replacement transducer disk Great replacement part for smoke effect fire.