Amplifier Replacement Cord For All PLT QD Compatible Headsets Connect H/HW series Plantronics headsets to their amplifiers, M12,M22,AP15's Will work with any manufactures brands that have the PLT QD, VXI P Series, Smith Corona P Series, Starkey PL Series, The One, Any PLT QD compatible headsets Contact HEADSET SOLUTIONS prior to ordering with any questions about compatability PLTQD on one end, RJ11 modular clip on the other - Dasan manufactured Can use these direct in on Cisco 7900 series phones with any PLT QD compatible headset