I got this earlier in the year to alleviate neck problems from using my phone at work. I called to find out if it was compatible with my VOIP phone and they said it was. It is absolutely not compatible with the Comdial ConversiIP EP100. This lifter is made for a completely different type of phone. I had to tape the lifter with packing tape just to keep it attached to the phone. While the earpiece is great, the lifter is the real problem. It has lazy days where it just lifts very slowly then it won't lower all the way. I have had problems since day one with the lifter not working well in addition to not fitting well. So, I would be wary. If I could return it I would.