Intcrown Bluetooth Headphones V4.0 Built in Microphone Wireless in-Ear Earbuds Headset for Running Gym Exercise (Black) Intcrown S520 Wireless Bluetooth Headphones are especially designed to provide you with the best experience of enjoying music while you are exercising. They are equipped with CSR Bluetooth V4.0 +EDL and DSP Noise cancellation technology. The earphones will stay in your ears snugly because of its unique diminutive size. It is the smallest size comparable to other similar products and it is 60% lighter than the other earphones statistically. It's perfect for all different types of sports, such as running. They have all the features you need: Mini Size, Super light weight, and great sound quality. The chord is just about the right length, easy to connect to Bluetooth that allows you to enable hands-free talking. In conclusion, you get full range of movement while maintaining good sound quality and pain free experience. 4 hours listen time, one hour charge time, and 10 meters working distance. Package contents: Intcrown S520 Wireless Bluetooth Headphones, User manual, USB charging cable, and Ear tips replacements.