Early Finnish heart-rate monitor. Seems clunky but was quite suave next to its Japanese rivals, which required a wire from the chest harness. If Amerec wearer exceeded 85 percent of maximum pulse, he was alerted by an alarm. Or subsequent vomiting.

First dead-serious "training" watch: countdown timer, multilap memory-all the features you need to swim, cycle, run, or pretend you do; 3.5 million still sell each year.

Original "skier's" watch, which meant elastic strap that stretched over parka sleeves and big, glove-friendly buttons.

For those who don't mind forking over $1,000 to have a machine count for them. Water activates computer, which then spits out navy dive-table calculations about bottom time and such. "Don't fly" indicator carps at wearer to stay out of planes till threat of the bends passes.

Measures elevation to 40,000 feet, barometric pressure, temperature, and vertical feet gained and lost, a plus for heli-skiers seeking barstool fodder.