These GPS units are identical, except the GT-31 uses a SIRF III GPS chipset. Delivery is expected by April 15, 2008.
These GPS units track 12 satellites every second. Garmin GPS units track only 4 satellites every 2 seconds. The differences between the 1 and 2 second satellite readings can be seen in the following GPS Trackpoint Comparison. More trackpoints yield more accuracy.
The GPS data is written to an SD memory card (not included). An entire season's worth of windsurfing can be stored on a single SD card.
These GPS units float and are water resistant. However, both require an Aquapac 208 Pro Sports Case for protection from the high speed crashes associated with Speed Windsurfing.
The GT-31 is also useful for jogging and hiking when used with the optional Armstrap.
These are also an excellent speedometer/odometer for bicycling with the optional Bicycle Handlebar Mounting Kit.
For more information, download: the GT-11 Quick Start Manual, and the GT-11 Owners Manual,
