I work in a small office environment, it is generally very quiet in here and I'd like to get some IEMs that don't bother those around me. Do noise isolation IEMs work in both directions, or do they only prevent noise from going out?

Hi Head-Fi, this is my first post and I am glad to be here :)   I have a pair of PC360's that I use for gaming and listening to music on a mid 2010 iMac. They sound great but unfortunately the microphone doesn't work because my iMac doesn't have mic in. I purchased a Logitech USB Adapter on...