Circle™ SC 230 MS II 506482 Circle™ SC 230 MS II is a single-sided wired headset for all-day use with a USB connector and certified for Skype for Business. It also features in-line call control. Specifications: Colour black Connector USB Frequency response (microphone) 150 Hz – 6,800 Hz Frequency response (headphones) 50 Hz – 18,000 Hz Microphone noise-cancelling Max. sound pressure level 113 dB limited by ActiveGard® Included in the box: Headset Acoustic leatherette ear pad Cable/clothing clip Quick guide Safety guide Nylon protective pouch