We have a CS1000, mostly 3904s. We've been purchasing the HL10 lifters for the M50 and they just do not work right. We've been searching for something which will work with our phones without the hastle of having to superglue or velcro the lifter to the phone. We need the wireless headset with answer from headset options. Has anyone had any luck or found something compatible? Ideal would be to find a company who could service these on site as well. Thanks for any advice.