I purchase two of these unit the first one work ok . the second one have a problem . in a side by side comparison the signal quality of the two unit vary . I check there accuracy and tracking with oziexplorer move map software . the first unit track pretty good , but the second unit position be off a large percentage of the time and sometimes as much as 400 meter . I send the faulty unit to Garmin to be repair . they send it back with a description of the problem and that it have be fix . I check the unit out and it be the same as when I send it to they . now I be stick with a dud .