They're great! This is a very simple one that I got at Wal-Mart for about $6. It keeps track of time, steps, mileage and calories burned. I have found it to only be accurate when I am actually out on a walk. If I clip it on when I am just walking around the house, it will say I walk 3 miles just unloading the dishwasher - haha! But when I am out walking for exercise, it is very accurate. And a great motivator!