16-300Ω HIFI Headphone Amplifier Portable Earphone AMP 3.5mm w/ Audio USB CableFeatures:1. The 16-300Ω HiFi headphone amplifier is exquisite, compact, light and easy to carry.2. 3.5mm AUX input and output, SNR>120Db and THD+N 0.0003%, not only can output louder sound, but also can output clearer and more realistic stereo without distortion.3. The two-stage gain switch enhances the signal input to the headphone amplifier circuit, so that the earphone achieves the best performance4. The aluminum matte surface and stylish design provide you with a comfortable hand-held feeling, while the aluminum matte surface makes it durable.5. Rechargeable lithium battery, using 1000mAH capacity rechargeable lithium battery, can work continuously for more than 8 hours. Specification：Maximum power output: 350mW  32ΩloadLoad impedance: 16-300ΩWorking voltage: DC3.7-4.2VCharging voltage: DC5VFrequency response: 20Hz-20kHz(±3dB)Battery capacity: 1000mAh (3,7V) Lithium-BatteryAmp Using Time: More Than 8 HoursDistortion: 0.004%SNR: ≥120dBDimension(L*W*H): 9.5*6.1*1.5cm/3.74*2.4*0.6in Package:1 x HIFI headphone amplifier1 x Charging cable1 x 3.5 audio cable1 x user manulPaymentReturn WarrantyShippingContact usPayment1. We accept payment via PayPal. Use PayPal at checkout to pay with credit or debit.2. Immediate payment is required. Shipping will be arranged within 1 business day once payment is cleared. Return 1. We stand behind our items and offer 60 days warranty. All items are in new and working condition unless specified otherwise elsewhere in the description.2. All Returns - defective or otherwise - MUST BE PREAUTHORIZED to guarantee refund or exchange. Please contact us to get an authorization and return address. 3. Buyer agrees to pay for the cost of re-shipment for undeliverable or wrong addresses. 4. Buyer is responsible for Return Postage as well as a 20% restocking fee if return/replacement is not a result of our mistake such as wrong item.5. Replacement or Refund will be made upon receipt of the returned item. Please include tracking number so we can process ASAP. If you do not wish to wait for a replacement, please repurchase the item. 6. ALL REFUNDS will be processed via PayPal. Please double check via PayPal history and transaction for confirmation. PayPal will send it back to whatever you used to pay within 3-5 days.WarrantyThe warranty shall not apply to the following circumstances:a) Damage caused by undue ware&tear, misuse, improper installation or operation, neglect, accidents.b) Damage caused by natural disaters, flood, fire, lightning or pollution.c) If item was opened, any parts removed or repaired by any unauthorized person.ShippingFREE SAME BUSINESS DAY MONDAY- FRIDAY SHIPPING FROM USA.All orders and payments received before 4PM EST (1PM PST) will be shipped the same business day.All other orders within 1 business day.No shipping on Weekends or US Public Holidays. No responsibility for any custom dutyShipping information will be updated when available.Contact usWe have always been trying to provide the best service and reliable products for every customer, however, accident may happen sometimes, please contact us to resolve any issue before leaving a negative feedback.