Feature: High-quality materialsl housing. matte anti-fingerprint, one-button non-slip rotary button, more comfortable touch and scratch resistance than plastic cover USB plug and play. 360-degree rotatable arc button, easy to use (volume adjustment, mute, up and down, pause), and avoid discomfort caused by sharp edges Non-slip mat. There is a soft pad at the bottom, which is stable and non-slip during use Lossless sound quality. Adjust the audio source directly without affecting the audio quality.suitable for use with desktop or laptop Broad compatibility. Support operating system for WIN 7/8/10/XP, for Apple, for VISTA, for Android, for iOS (mobile phone needs a suitable universal serial bus adapter cable) Specification: Name: USB volume controller Installation method: USB driver-free Mode: button to switch dual mode Applicable to: for Windows, for Mac OS Note: If your device can use a USB mouse and keyboard, you can also use our USB volume controls. Material: plastic colour: Black Package Contents: 3 x PC Computer Speaker Volume Controller Knob Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.