Long-distance runners, especially marathon runners, will want to check out the Adidas RPT-01 Bluetooth Sport On-Ear Headphones ($100, originally $170). While the Bluetooth wireless headphones score low (IPX4) on the water-resistant scale, the key feature is the 40-hour battery life. Amazon customers rave about the headphones' long-lasting battery, giving the headphones a near-perfect five-star rating. Additionally, the ear cushions and inner headband are removable for easy washing.