Summary: Top of the range GPS, value for money.. Started to use a GT11 4 years ago, after 2 years I went to the GT31 which is in MPOV the most accurate, compact, versatile, waterproof GPS on the market. There is a bluetooth version but don't bother with it. It is also the No1 GPS being use in worldwide pro speed windsurfing. This GPS can be used anywhere in any speed, distance sports. I just bought a second one to be used in pairs with the other one.