An Alti Variometer is one of the first pieces of ancillary equipment a pilot will buy. It has an altimeter in combination with a pressure related variometer, basically tells you when you are in lifting or sinking air! There are a huge range to choose from with a variety of features. Even Basic models these days will have a choice of 2 or three Alti settings, have peak and average settings, Audio with varying thresholds. On more advanced models GPS is combined to give Information on Location,speed, glide over ground, airspeed. Drift, windspeed,and competition turn points can be entered. You can also download this data to a PC to give a 3d track on google earth, etc using gps dump. They will also have the possibility to have the track logs downloaded and viewed on a PC.