This complete wireless doorbell kit includes a plug-in receiver and a PIR motion detector transmitter for convenient, cable-free installation. The receiver plugs into any standard 110-240V AC outlet, while the transmitter is powered by 3 AA batteries (included). Choose from 38 pleasant melodies and adjust the volume to high, medium, or low settings on the receiver, which also features a sound/silent mode with an indicator light. The system provides a reliable wireless range of up to 70 meters in open spaces. The motion sensor detects movement within a range of 3 to 7 meters. For optimal performance, install the sensor at a height of about 2 meters using the included adjustable bracket. Side or top mounting near an entrance is recommended, as horizontal detection is more sensitive than direct frontal detection. **Installation & Guidelines:** 1. Plug the receiver into a power outlet. Insert batteries into the transmitter and slide its power switch to ON. Wait 10 seconds for the self-test. 2. Attach the transmitter's bracket and mount it in your desired location. 3. For best results, avoid pointing the sensor at direct airflow, heat sources, sunlight, rain, or metal objects. 4. To maintain signal strength, minimize obstacles and wireless interference between the sensor and receiver. Note that walls can reduce the effective range to approximately 20 meters. 5. If experiencing a short range or malfunction, check or replace the transmitter batteries. **Dimensions:** * Receiver: 76 x 80 x 33 mm * Transmitter: 80 x 59 x 45 mm