This is SHOKZ OPENRUN PRO 2. I purchased it on November 11th at an electronics store. I bought it, but I haven't used it at all, so I'm selling it. It's the standard size. It has dual drivers, and the sound quality is very good, with almost no tingling sensation typical of bone conduction. It's comfortable. • Used less than 10 times • Not used outdoors • No scratches • Alcohol-disinfected • Receipt from purchase available • Accessories included