The WF-C510 earbuds are optimized to perfectly match the human ear. Small and cylindrical, the charging case is made to fit in your pocket or your bag. Enjoy superb comfort and an even better fit, thanks to their rounded shape and reduced surface area. This Small, light, and great fit, WF-C510 is the most compact ever closed-type truly wireless earbuds. The Sony WF-C510 Truly Wireless Earbuds in Yellow feature a compact and light design for a comfortable fit.