The iPhone Stereo Headset was introduced in 2007 and was bundled with the original iPhone and iPhone 3G, and featured a control capsule in-line with the right earbud’s wire with a microphone and a single button, actuated by squeezing the unit.
EarPods were introduced on September 12, 2012 and feature a redesign with no silicone tips, less visible metal, and a plastic outer shell. They first shipped with the iPhone 5 and feature a remote control and microphone.
A microphone icon was added on the previously unmarked back side of the control capsule on EarPods with a microphone.