the device be difficult to use for the average person and the manual do not give very good instruction . also , I have have random problem . after take a full charge , it shut down the next morning in the first 5 minute of my workout . then on my next workout , it show the time and distance , etc. . . during the workout , but fail to record any of it to history , so the datum could not be view later . I do not find the feature describe in the manual to be useful and try to just use the basic feature of record workout seem to be hit or miss base on random problem . in try to email customer support , I continually receive notice that the system be not work and to try back later . I guess I 'll try call for support . I would not recommend this device .