There is so much to love about the Bose SIE2i headphones - they were clearly designed with athletes in mind. Unlike many sport headphones I've tried, these fit comfortably in my ears without fully blocking out the outside world. This makes me feel safer running outside, without losing any of the superior sound quality I would expect from Bose. They are sweat-proof and water-resistant, making them ideal for sweaty workouts or runs in New England weather. The Reebok armband makes taking my iPhone along effortless, and the touch-sensitive case works perfectly. Extremely happy with this product!