Feature: Super mini size, easy to carry. Very easy to use: just call the SIM number installed in the device. Within seconds, you can hear audio from a 10-meter radius. GSM Quad Band (850/900/1800/1900 MHz) ensures worldwide compatibility. Built-in dual microphone for clear sound quality. Supports preset phone numbers. Element type: Two-way audio device. Acoustic alarm function available. Long standby time: built-in 200mAh lithium-ion battery lasts 3-5 days with acoustic alarm enabled, up to 12-15 days when disabled. Materials: Molded plastic. Dimensions: 4.3 x 3.2 x 1.4 cm. Power: Built-in 200mAh lithium-ion battery. Color: Black. Voice activation duration: 3-5 days with alarm on, 12-15 days with alarm off. Working hours: up to 5 hours. Microphone range: 5-7 meters radius. Package includes: 1x two-way audio device, 1x USB cable, 1x user guide (English). Note: Color may vary slightly due to monitor settings. Our products are made with high-quality materials and designed for optimal performance. We aim to ship orders within three business days. Estimated delivery time is 8-15 days. Please review product dimensions before purchase. Detailed information is provided in the title and specifications. Customer satisfaction is our priority—feel free to with any questions. Thank you for choosing our product.