KOSS PRO/4AA Monitor Headphones The thin sponges on the front of the left and right speakers are not present. (Set to "slightly scratched or dirty.") Ear pads replaced. Sound output from left and right confirmed (Please note that I am a novice regarding detailed sound quality.) ✳︎*⭐︎✴︎These headphones have a unique, military-like form✳︎*⭐︎✴︎ The following is a reprint from the internet: Since its release in 1970, this professional standard model has undergone numerous improvements. With its unchanging form, it has gained high trust over many years as a monitor for recording engineers and broadcast engineers. ＜Features＞ ■ Heavy-duty and high reliability, recognized as a professional standard, with numerous improvements since its release. ■ Uses a 25mm voice coil and a 50mm large diaphragm. ■ Achieves clear sound monitoring with the adoption of new Mylar high-sealing ear pads. ■ Suitable for use in acoustic environments such as live venues due to the high sound insulation effect of the ear pads. ＜Specifications＞ ■ Type: Dynamic ■ Type: Closed-back ■ Impedance: 250Ω ■ Sensitivity: 95dB SPL/1mW ■ Frequency Response: 10～25,000Hz ■ Cord: Curly cord / 3m ■ Plug Shape: 6.3φ stereo standard ■ Weight: Approximately 595g (excluding cable) Type: Headset Connection Type: Wired Structure: Closed-back Noise Canceling: None Gaming: Not gaming compatible Weight: 400g〜