On the back of the headset is a round earpiece with a rubber ear bud cover. The cover has a loop attached to it to secure it in the folds of the ear. There are three different ear bud covers for different size ears. You also have an optional flexible ear hook for a more secure fit, but we found the hook to be quite flimsy. So flimsy, in fact, that it broke when we were trying to adjust it. Thankfully, you don't need the hook to wear the headset properly.
We paired the LG HBM-900 with the Apple iPhone 3G. The pairing process was smooth, as the headset automatically goes into pairing mode the first time it's powered on. The triple microphone setup on the HBM-900 definitely works to cancel out background noise, if our callers are to be believed. They said we sounded loud and clear, and couldn't hear the din of engine noise when we were in the car. Still, audio quality wasn't perfect. They said our voice sounded tinny and harsh, with the occasional crackle. It also does not handle wind noise very well at all. On our end, we could hear them just fine, though we did detect a tiny bit of static at times.
Features of the HBM-900 include the normal answering, rejecting, and ending calls. There's also last number redial, voice dialing support, call waiting support, auto connect, multipoint technology that lets it connect up to two devices at the same time, and auto volume control.