It is a bluetooth speaker as the outdoor riding mate. You can use it to listen music when you are bicycling or have a picnic, camping. It also be used indoor. Hopestar p4 speaker can be as a mobile power bank. It's capacity can charge twice for iPhone. Hopestar p4 speaker has emergency flashlight function. It can be used as a temporary spare flashlight when you suddenly enter a dark environment. Hopestar p4 speaker support TF card. Hopestar p4 speaker has FM fuction. (FM function will better when it is plug in audio cable) . Hopestar p4 speaker has IP55 waterproof and dustproof skid Feature. Key Specifications include : 1. Battery capacity: 4000mAh , 2.Bluetooth Version: CSR 4.0 , 3. Transmission distance: 10m, 4. Input voltage: 5V/ 1A Output voltage, 5. LED Lamp-Power : 1 W , Work voltage: 3.7V,6. 3 LED modes: Normal, Weak, Flash, 7. Speaker: 4Ω ,8. SNR: ≥90dB, 9. Frequency response: 20Hz - 20KHz, 10. Distortion: 1% 11. Integrated Omni Directional MIC : Frequency Range : 50 Hz ~2.5 Hz , MIC Sensitivity : 38 DB 12. Size: 156 x 51 x 51 mm , 13. Weight: 260