Bluetooth function. Works with wired 3.5mm audio jack headphones. Compatible with older iPhone models that have a Lightning port. Suitable for : iPhone 5, 5c, 5s, 6, 6Plus, 6s, 6s plus, SE, 7, 7 plus, 8, 8 plus, X, iPad mini2, air, air2, mini3, mini4, pro (9.7), pro (12.9). Package Size : 10 x 2.8 x 0.5cm.