This 50 pack of the durable and sleek deluxe Smart-Trek™ USB headsets are highly versatile and compatible with a wide variety of technologies including PCs, Macs, Chromebooks and most Gaming Systems. Designed to stand up to the K-12 environment, Smart-Trek™ headsets are built to last. The Smart-Trek™ series features a rugged and comfortable design, so teachers can have headsets that will function for years, and students can wear the headsets for an extended period of time. The Smart-Trek™ headsets come with an easily adjustable headband to fit students of all ages; ear cups made with high-quality, supple-soft leatherette ear cushions that are easy to clean, durable, and provide excellent noise-isolation; a durable, flexible, noise-canceling steel-reinforced gooseneck microphone; and Dura-Cord™ – the chew, kink and knot-resistant, PVC-jacketed, braided nylon cord." "Drivers: 40 mm Impedance: 32Ω Frequency Response: 50Hz - 20KHz Sensitivity: 100dB±4dB Warranty: 1 Year 5' Dura-Cord™ - chew-resistant, PVC-jacketed, braided nylon USB plug Microphone Specifications: Omnidirectional Passive noise cancelling microphone Steel reinforced gooseneck mic Sensitivity: -50 ±2DB Frequency response: 50Hz-16Khz Impedance: 2.200Ω"