This Telephone Headset only comes with RJ9 jack. It Only works for Cisco Landline Phones. Not for Cell Phone and Computer. Attention: This RJ9 Phone Headset doesn’t come with 2.5mm jack, 3.5mm jack or USB jack. Compatible Phone List (Include but not limited): DO NOT BUY THE ITEM IF YOU CAN’T FIND YOUR PHONE MODEL IN LISTS, CONSULT US FOR COMPATIBILITY ADVICE. Compatible with: Compatible with Plantronics: M10, M12, M22 & MX10 Amplifiers Compatible with Cisco: Cisco IP Phones: 7931G, 7940, 7940G, 7941, 7941G, 7942, 7942G, 7945, 7945G, 7960, 7960G, 7961, 7961G, 7962, 7962G, 7965, 7965G, 7970, 7970G, 7971, 7971G, 7975, 7975G, 6821, 6841, 6851, 6921, 6941, 6945, 6961, 7811 7821, 7841, 7861, 8811, 8841, 8845, 8851, 8861, 8941, 8945, 8961, 9951, 9971 NOTE: Not Compatible with Cisco Spa Phone Series and Cisco 7905G, 7906, 7906G, 7910, 7910+SW 7911, 7911G Crystal Clear Chat The RJ9 phone Headset with Noise Cancelling Microphone to reduce background noise, a flexible mic boom to suit your preference. Features a truly clear, natural and rich audio for calling. All Day Comfort The Corded telephone headset with super soft high quality leatherette ear cushion and Rotatable Earpiece enhances long-time wearing comfort. Adjustable headband to fit all head sizes. Super Lightweight The Landline phone headset weighs only 2.3oz, brings no burden to your head and ear. 330° rotatable mic enables you to wear on either the left or right side.