Plantronics Amp For H-Series - Plantronics Vista M22 universal modular adapter- Replacement for the PL-M12- Enhanced features over the M12- Modular jack plugs into phone- For use with any Plantronic quick disconnect headset- Operates on 2 AA batteries (included) or AC adapter (not included)- Manual scroll volume control - Headset on/off switch (switches between headset and telephone handset)- Mute button- Clear Line Audio technologyEnhanced Features over M12- Wideband audio (totally compatible with existing systems and "wideband ready" to deliver superior audio on integrated wideband (VoIP) systems)- Protection from loud noises (delivers greater protection against sudden loud noises by quickly reducing them to comfortable levels)- Phone line noise reduction (filters incoming and outgoing phone line noises, such as high-frequency hissing, making conversations clear, less fatiguing and more comfortable)- Call volume equalizer (equalizes the level of all calls to the same comfortable, user-preferred listening level)- Echo management (eliminates echo problems introduced by latency in IP networks; so even if your new IP phones do not require an Amp your conversations may still benefit from the use of one)- BlackADDITIONAL/REPLACEMENT PARTS:PL-ADAPTER (PL-26503-01): AC adapterPL-40696-01: amplifier security device (attaches amplifier to desk)PL-26609-02: slide switch door and battery doorPL-40974-01: amplifier to telephone coil cablePL-40715-01: custom cradle matePL-26716-01: amplifier to QD coil cablePL-17521-01: velcro attachment kitPLM22