Product parameters: Product Name: Violent Fan model: F9 Battery capacity: 3000mAh * 2 Working voltage: 6~8.4V Charging time: 2.5h Product size: 143 * 39mm Product weight: 315g Gear adjustment: 100 speed infinite speed regulation Contact us: 1. We will leave POSITIVE FEEDBACK after receiving the payment. Please contact us if you are not satisfied with the item after receive it. 2. All messages will be answered within 1 business day. If you do not receive our reply, please kindly re-sent your message and we will reply to you as soon as possible. 3. If you have any problems or concerns whatever with your order or products, please message us and give us a chance to assist you before you leave any feedback. 4. We believe we can produce a positive outcome to any situation and will work hard to earn your praise. We strive for 100% customer satisfaction! Positive Feedback is very important to us. Your satisfaction is our pursuit. If you have any questions and needs, please contact us at any time. Our professional team will answer every doubt for you. We will reply to you within 24 hours. If you have a problem on the weekend,Don't worry, we will reply to you immediately after working on working days.