... 4.ATC testing ,CE certificate,ISO9001:2008 VCOM Professional Mini Speaker Product Feature: Frequency:150~18KHz Imdedance:4Ω Distortion ... quality at every stage of production, from the incoming raw materials to the finished product. · QC Staff: 10 ... Board.Categories of computer electronics: Headphone, Bluetooth Headphone, Earphone, Speaker, Mouse, keyboard,Game Headphone and Keyboard, Game Mouse, Gamepad ...