Hosa HPE-325C Coiled Headphone Extension Cord. Stereo 1/4″ Phone Male to Stereo 1/4″ Phone Female. Extends to 25 feet.

Nickel-plated contacts for rugged durability and efficient signal transfer
Oxygen-Free Copper (OFC) conductors for enhanced signal clarity
OFC spiral shield for effective EMI and RFI rejection and flexibility