Built-in 2200mAh rechargeable 18650 battery, long-lasting performance, safe and environmentally friendly Durable construction with double-layer design; 3.5mm plug made of high-strength metal; PVC-insulated cable with strong tensile strength and effective shielding Dual-slot design supports both U disk (USB flash drive) and TF card (microSD card); compatible with computers, tablets, and smartphones Plug in a USB flash drive or microSD card for continuous playback—ideal for repeating audio clips, music, or learning materials Suitable for teaching, tour guiding, presentations, public speaking, promotional events, and training sessions Product name: Multi-function loudspeaker Input signal: microphone input Battery capacity: 2200mAh (18650 lithium-ion battery) Playtime: up to 20 hours Charging time: approximately 3 hours Applications: teaching, tour guiding, conference, training, music playback Dimensions: 9.2 x 8.4 x 2.8 cm Material: ABS plastic Color: Black Package includes: 1 x loudspeaker 1 x headset microphone 1 x carrying strap 1 x charging cable 1 x English user manual Note: Actual product color may vary slightly due to screen settings and lighting conditions. Slight measurement variations of ±1–3 cm may occur.