ZEALOT is a professional electronic Bluetooth speakers, Bluetooth headset company. We have professional R & D team, sales team and customer service. S1 is a new product. 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. S1 can be as a mobile power bank. It's capacity can charge twice for iPhone. S1 has emergency flashlight function. It can be used as a temporary spare flashlight when you suddenly enter a dark environment S1 support TF card.It has FM fuction. (FM function will better when it is plug in audio cable) S1 is IPX5 waterproof and dustproof skid Feature: Battery capacity: 4000mAh Bluetooth Version: CSR 4.0 Transmission distance: 10m Input voltage: 5V/ 1A Output voltage: 5V Output power: 3W Work voltage: 3.7V LED lamp power: 1W 3 LED modes: Normal, Weak, Flash Speaker: 4 SNR: 90dB Frequency response: 20Hz - 20KHz Distortion: 1% Music time: 5hrs Standby time: 30 days