Instruct: Classify a given Amazon review as either positive or negative.
Query: Doesn't work with iPhone 4

Tried to use this headset with my iPhone 4 and this MX500C headset picks up electrical noise constantly. My Plantronics M214C Headset with Adjustable Volume works OK. With both of these headsets an adapter is required for use with the iPhone 4 3.5mm headset jack. I used [Headset Buddy: 2.5mm Phone Headset to 3.5mm Adapter - Convert 2.5mm Headset to 3.5mm iPhone, Blackberry, Palm].