The Callaway idTECH Rangefinder provides range information during a round that allows a golfer to club correctly regardless of up/down slope of any shot. The newest addition to the Tour Authentic Series is used by pro staff and caddies to make yardage books when mapping a course. idTECH has a measurement range of 11-550 yards and contains incline/decline technology. After acquiring the range of your chosen target, idTECH will display the actual yardage and the additional or subtracted yardage amount to correctly club the shot.