1/8 Inch Stereo Audio Amp With Ultra-Compact Portable Mini Jack 3.5 Splitter Hup Product Details ?Instructions for use? Use scenario: 4 people listen at the same time, two playback devices, 4 people can freely control the volume ?2 in 4 channel out stereo headphone amplifier? is a 2 channel mixer with 4 high-power stereo amplifiers, each channel output level control, each channel can independently control the volume, the minimum volume can be regarded as closed, 3.5MM headphones and Or 6.35MM headset (requires a 3.5MM to 6.35MM adapter). ?Compact Design?6.7 in*2 in*1.26 in, Weight: 7.8 oz ?Good Sound?Contains 4 independent stereo high-power 5x amplifiers (14db), which can maintain the highest sound quality even at maximum volume. Adopt NJM4556A low voltage high current dual op amp, ultra low noise op amp for excellent audio performance: same as op amp in large size audio equipment ?Accessories?Equipped with 12v 1a power adapter Payment We accept PayPal and credit cards via PayPal. Taxes - US We collect sales tax, as required by law. Shipping We make every effort of shipping within 3 business day of payment clearing. The estimated delivery time is 2 - 5 business days from the shipping date. Policies If you do need to return your item, please contact us via email (you will receive an email when your product ships with additional details - Subject: Important information about your purchase). You will then be provided with a return shipping label and packing slip. Pack the item carefully. Include the packing slip, apply the shipping label, and return the item within 30 business days of the date you request a return, or your return will be canceled. Once we receive your order we will inspect the return. Please allow up to 5 business days of receiving the returned item for your refund.