Check the listing for details. Soldering Practice Kit, 1 Set Electronics Project DIY Musical Doorbell Kit , 3V. Condition: New. Listed at 11.70 USD. This DIY musical doorbell soldering kit electronics practice board is a teaching kit for people who want to improve the welding skills.An interesting DIY welding kit that can be used as a gift.Specification:Product:Electronic Production Soldering Teaching KitApplicable voltage: 3VSize: 93*67*28mm/3.66*2.64*1.1 inchEffect: DIY Musical DoorbellPacking List: 1 Set DIY Electronic Experiments Teaching Kit(Packing List: 1 * casing, 1 * positive electrode, 1 * negative electrode, 1 * positive and negative electrode, 1 * music film, 1 * transistor, 1 * capacitor, 1 * button, 1 * horn, 2 * spring, 4 * screw, 1 * PCB, 2 * terminal)Advantage :The circuit of this device uses 9300 or S-088BD series music films, and the sound is amplified with a power amplifier transistor 9013, resulting in a loud sound.