Summary: very nice look altimeter is worst than you could imagine compass is very easily effected by any magnetic field even by a small electric current , magnetic compasses are less sensitive, it works very good but away from everything gps looses signal very easily ! even outdoor ! when it has signal it works very good (i cross check it with another gps device). very frendly menu i only used it a couple of months now i cant say how reliable it is. very expensive.