Ultralight (34 g) & small (39x 64x 12 mm) Measures speed/pace & distance Records accurate GPS positioning data Easy to wear in a soft & flexible armband (26 g) Rechargeable (20 hour life) via micro USB The extremely small G5 GPS sensor provides accurate speed & distance measurement for a range of outdoor sports. It is light & easy to wear in the armband pocket. After training you can see your route on a map with compatible software/web service. Compatible with RCX5