Power Requirements: DC voltage 5V (4.8-5V), current at least 2A. (If powered from USB, the power supply itself must be capable of at least 2.5A, and the power cord must be able to handle this current. Sometimes, even with this much current, the cord can/t handle it.) Secondly, use genuine power banks from genuine manufacturers, and ensure the discharge capacity meets the standards (this is because these products use lithium batteries that are boosted). Counterfeit power banks not only lack current capacity, but also have unstable constant current. In particular, their transient current capacity can be insufficient (resulting in poor performance or distortion), which can easily damage the circuit board. Be careful! Speaker Requirements: (Satellite) Left and Right Channel Subwoofers: Use 4 ohm/5W full-range speakers. (Use 4 ohm/3W for USB power.) (WOOFER) Subwoofer: Use a 3-4 ohm/10W-15W subwoofer. Do not use 6-ohm or 8-ohm subwoofers. (Use 4 ohm/5W for USB power.) Audio Source: PC, MP3 player, or mobile phone are acceptable. The woofer is housed in the main cabinet, and the two full-range sub-enclosures house the two full-range speakers. These three should be kept separate. It/s recommended to have a 50-60mm bass reflex port in the main cabinet. Choose a wooden cabinet. The woofer must be properly matched and installed in the cabinet, with the bass reflex port properly secured. Ensure all seals are in place. Pay particular attention to the speaker/s impedance, diameter, and height. If the impedance and diameter are not appropriate, the note travel will be insufficient. Color: As the pictures show Size:4.8/4.8cm Package quantity:1Pc Note: Please allow 2/-3/ differences due to manual measurement. The above dimensions are for reference only. As different computers display different colors, thank you for your understanding, the actual product color may be slightly different from the image.