About this item 3.5mm Stereo Inline Audio Volume Adjuster: Provides precise volume control for your audio devices with standard 3.5mm stereo connections. Quick and Easy Inline Volume Control: Makes adjusting audio levels simple and convenient without reaching for your device. Large Serrated Easy to Grip Knob Audio Attenuator: Features a textured knob design that ensures comfortable and secure grip during volume adjustments. Versatile Audio Applications: Compatible with headphones, aux jacks, laptops, tablets, phones, PCs, MP3 and CD players, and any line level audio equipment. Compact and Durable Design: Measures 1.38 x 1.38 x 0.59 inches with tough ABS case construction held together with screws for long-lasting performance. No Batteries Required: Passive inline volume control that works without any external power source or batteries. Dimensions: 1.38 x 1.38 x 0.59 inches.