Headphones allow you to listen to music from your T-Mobile G1 device and if your G1 device and headphones support A2DP then you can use the same headphone for G1 device calls. Most common types of headphones are in-ear ear buds other there are other types as well including on-ear headphones that stay on your ear or around-ear headphones that form some sort of a suction around your ear. In addition to wired headphones there are Bluetooth headphones that are without wires.
