The A4Tech HS-28i is a 4-pin 3.5mm combined audio headset that connects to devices with a single 3.5mm TRRS audio jack (common on smartphones and newer laptops). It delivers clear stereo audio along with a built-in microphone for calls and voice communication. The adjustable headband and padded ear cups provide comfortable long-term wearing. Compatible with smartphones, tablets, and laptops with a 3.5mm combo jack. Note: This model does not include a PC splitter cable adapter. Great for users who want a universal headset for mobile and compatible laptop use.