This RJ9 Office telephone headset is a 4-Pin RJ9 Crystal Jack Headset, it is ONLY compatible for CISCO landline phones, NOT for Smartphones and Computers. Attention: This RJ9 Phone Headset doesn’t come with 2.5mm jack, 3.5mm jack or USB jack. Please read the compatibility information carefully before purchasing. For other phones, please Consult us for Compatibility Guide or Advice. Compatible Landline Phone List: Cisco IP Phones: 7920, 7931G, 7940, 7940G, 7941, 7941G, 7942, 7942G, 7945, 7945G, 7960, 7960G, 7961, 7961G, 7962, 7962G, 7965, 7965G, 7970, 7970G, 7971, 7971G, 7975, 7975G, 7811 7821, 7841, 7861 6821,6841, 6851, 6861, 6871, 6921, 6941, 6945, 6961, 8811, 8841, 8845, 8851, 8861, 8941, 8945, 8961, 9951, 9971, 12VIP, 30VIP, 8865, CTS 500 Plantronics Amplifier: M10, M12, M22 & MX10 Amplifiers Panasonic: KX-UTG200B, KX-UTG300B NOTICE: NOT compatible with Cisco Spa phone series and Cisco 7902, 7905, 7905G, 7906, 7906G, 7910, 7910+SW, 7911, 7911G, 7912 IP Phones. The video showcases the product in use.The video guides you through product setup.The video compares multiple products.The video shows the product being unpacked. Previous page Super Lightweight Weighs only 56g/1.97oz. Ultra-lightweight landline Cisco headset minimizes the burden of wearing. Soft Ear Cushion Soft and breathable leatherette ear cushion makes you feel all-day wearing comfort. Adjustable Headband Flexible headband can be bent or shaped for all head sizes to relieve the pressure from headset. 330° Rotatable Microphone Flexible and 330° rotatable mic can be placed on the left or right side for better voice capture. In-Line Controls Simple in-line controls allow you to easily adjust the volume & mute mic to make your calls easier. Next page 1 Super Lightweight 2 Soft Ear Cushion 3 Adjustable Headband 4 330° Rotatable Microphone 5 In-Line Controls Crystal Clear Calls High sound quality Cisco office telephone headset provides natural and truly clear conversations, Noise Cancelling Microphone reduces background noise and Acoustic Shock Protection (ASP) protects your hearing. Free up Your Hands Full days online hands-free talking. Callez Cisco landine phone headset allows you to continue to work on other tasks while taking calls. It's a practical and good companion for business, reducing fatigue and making your work easier. How long is the headset cable? The cable of this rj9 landline phone headset cord is about 77 inches / 6.4 ft, and there is an extension coiling cable, so you can extend the cord to about 83 inches / 6.9 ft. Thank you. Is there a mute button on the headset? Yes, this cisco phone headset has a microphone mute button and volume control that allows you to mute/unmute the microphone and adjust the volume. Can it be worn on on either ear? Yes, it can. The microphone of this rj9 telephone headset can be 330°rotated for you to wear on either the left or right side. Does it work with a mobile phone or laptop? No, it can't be used with computers or mobile phones. This 4-pin RJ9 phone headset can only be used with some specific CISCO landline phone models listed in the description. Is this headset compatible with Cisco SPA 504G phone? No, this rj9 headset doesn’t work with Cisco SPA 504G and Cisco Spa phone series, it is only compatible with Cisco 7931G, 7940, 7940G, 7945G, 7960, 7960G, 7961, 7961G, 7962, 7975 etc. SEE MORE COMPATIBLE CISCO MODELS LISTED IN DESCRIPTION.