Nike+ Stand Alone Sensor Kit Compatible with Mac OS X v10.3.9 or later, Windows Vista, or Windows XP (SP2) Home or Professional Simply place the Nike+ Sensor under the sockliner of your left Nike+ ready shoe and start running to sync it with your Nike+ Sport Watch GPS, iPhone 3GS or other Nike+ tracking device. Measures your pace, distance, time elapsed and calories burned. Not compatible with iphone 6 and 6 plus.