Good product for its simple and convenient operation providing the information necessary for regular runners: mileage, pace or speed, time traveled. On marathon (42.195km), it commits an error of about 200m that I do not find that important. For cons, the margin of error is much greater on track. So it is a good product for the road or even in the forest, do not use on track. Problem: I do not know if it's due to my excessive sweating or ambient moisture in Guyana, but I bought this product in June 2012, have returned to France in December GARMIN, have recovered January and again in September same problem: load problem, and does not light up. But this product, guaranteed for 2 years I have been repaired by Garmin the first time and exchanged by Amazon.com the second time. So do not fear his purchase since both companies are showing real effective service. Thank you.