The neck-wound bone conduction earphones are very suitable for sports wear, but the traditional bone conduction earphones have a single shape, and their volume is often not as small as other types of earphones, which is inconvenient to carry. We found inspiration from the folding storage of glasses and designed a rotatable and foldable metal rotating shaft, which successfully reduced the volume of the earphone by half. At the same time, the flat folded state is more convenient to carry and can be carried in your pocket. The earphone has a small shape, smooth lines, and a sound unit shaped by water droplets. It is extremely comfortable to wear with skin-like silicone material. It has IP67 waterproof and sweat-proof, making it a particularly excellent bone conduction sports earphone. It solves the problem that the bone conduction earphone is too large and difficult to carry; by rotating and folding, the volume is reduced to half of the regular earphone, which can be easily carried in a pocket. Compact and lightweight, comfortable to wear, the headset weighs only 30 grams.