Designed to wirelessly stream music to Bluetooth earbuds as you run, bike, hike, swim, or even train indoors, the TomTom Spark Music Plus Cardio GPS Watch is a multi sportactivity tracker watch with 3GB approximately 500 songs of built in storage for loading all your favorite workout tunes. This watch is compatible with both MP3 and C what iTunes uses files, meaning it'll load music from both Windows Media Player and iTunes, as well as many other popular music libraries on both Mac and PC. Its Bluetooth Smart sensor wirelessly streams music to Bluetooth equipped earbuds with A2DP and AVRC profiles. Check your earbuds' specifications to ensure compatibility Bluetooth earbuds sold separately. The black and white LED screen offers an easy to read display in both bright outdoor environments and indoor gyms with dim lighting. An intuitive leftright button interface effortlessly toggles through the watch's different displays and workout screen menus. Its built in heart rate monitor, GPS tracking, and motion sensor records heart rate, speed, pace, distance, calories burned, and workout duration when you're cycling on twisty roads, running along your favorite trails, cardio training indoors on a treadmill or stationary bike, as well as swimming laps in the pool it's rated at 5 ATM water resistance. Besides monitoring important exercise statistics while you work out, this watch acts as a 247 activity tracker that monitors your steps taken every day, active minutes, calories burned, and sleep schedule. It also functions as a training watch for pushing your limits, offering Race, Goals, Zone, Laps, and Interval modes for competitive use. Additionally, it comes bundled with a USB chargingdata transfer cable and user guide. Please note that it comes in two strap sizes, with the recommended wrist size for each respective strap noted in the dimensions specs on the left side of the product display page.