To designer, curve is the geatest gift from nature. Curve belongs to God. There is no straight line in the body of vkworld X3310. Each curve on the body is exactly perfect for your palm. Whenyou hold the phone in hand, you will not think it as a phone. You will feel it more like a pebble or a soap. Headphone jack Headphone Interface Support 3.5mm standard. Standby Time Standby time 150 hours.