【Excluding Mobile Phones and Computers】Please refer to the list of compatible phones in the description. [Not applicable to mobile phones and computers] Direct-connect landline headsets are only compatible with specific phone models from Avaya PLT Polycom Zultys Gigaset NEC Mitel Alcatel TSB. 【Clear Calls】The wideband sound 4-pin RJ9 phone headset with a microphone provides excellent sound quality and a natural listening experience. The noise-canceling microphone reduces background noise, and the acoustic vibration protection circuit protects your hearing. If you can hear the other person's voice but they can't hear you, there may be a compatibility issue between the headset and the phone. Please use one of the three included adapters, connect it to the headset's adapter, and then insert it into the phone's interface. Use one of these three adapters to check if your voice is reaching the other person. 【Comfortable Headset】Ultra-lightweight wired hands-free RJ9 office phone headset with an adjustable headband to fit all head sizes. __________________________________________ ★Please understand that this product's functionality is unconfirmed before purchasing! ＊Instant purchase welcome, silent purchase at midnight OK◎ ＊First come, first served for single items ＊Bulk purchases welcome, feel free to comment ＊Free shipping! ・Please understand that items are stored at home and shipped in simple packaging. (⁎ᵕᴗᵕ⁎) ・Please check the actual photos for the condition of the product♪ ※To offer the lowest possible price, we may ship the item without the box due to shipping costs. #Yudetamago's product list is here ✨☜ 　　Follow-up discount, bulk purchase discount available★ 　　Please shop at a great value!! __________________________________________ Wantek Headset for Telephone, Single-Ear, Fixed-Line Phone Headphone with Noise-Canceling Microphone, RJ9 Call Center Phone Headset, Compatible with Avaya PLT Polycom Zultys Gigaset NEC Mitel Alcatel TSB 19-6 3499 ☆