Hands-free earpiece with in-ear design. It consists of:

An earbud: Fits snugly inside the ear canal for potentially better noise isolation.
An earhook or clip: Attaches the earbud securely to your ear for comfortable wear.
A cable: Connects the earpiece to a device (phone, music player) via a standard 3.5mm jack
A microphone : Integrated into the cable or the earpiece itself, enabling hands-free calling.