Used by professional golfers, this watch identifies imperfections in your golf swing and helps you improve your stroke. The watch measures tempo, rhythm, backswing length, and club-head speed and instantly displays metrics for each on the watchface. After hitting a good shot, you can use the measurements as benchmarks for consistent, optimal ball-striking and to quantify the elusive "perfect swing." Three accelerometers (similar to the technology NASA uses to monitor the movements of astronauts in space) record 200 measurements per second--from the start of the backswing until ball contact--and use proprietary algorithms to determine if your backswing is a few degrees too long or your tempo is off by as little as 1/100th of a second. The watch records swing measurements for each club in your bag, it has four scorekeeping modes, retains handicaps for two golfers, and records separate statistics for tee-shots, fairway-shots, and putts. The watch has clock, calendar, alarm, and stopwatch functions. Water resistant down to 100'. Battery included.