Bolsen 5PCS 20/25mm Ultrasonic Mist Maker Fogger Ceramic Discs with Wire & Sealing Ring - DIY Humidifier, Fountain, Aromatherapy Diffuser for Home, Spa, and Indoor Plants

The quality of this ultrasonic piezo speaker appears to be good. I replaced the dead speaker in a cool mist humidifier with one of the ones from this order, and after ~15 minutes of nothing, the humidifier started working as good as new, and has continued to work normally ever since.As of 20241208, it's barely been 24 hours since I installed this part, and so there's nothing to say about long-term durability. I'll update this review as I know more.