I'm on my second monitor (and still pre-surgery, too!) so far. The first was a Timex "Iron Man" series. About $70 via the Timex web site. I used it for about 2 or 3 years. I changed the battery in the chest strap numerous times -- it didn't seem to last more than about 6 months, but I could buy them at the drug store. When the strap began to fall apart, I decided to try a Polar. The unit seems to be well made and easy to use, and is the basic one. It has no model number on it, so I can't be more specific. My only concern with the Polar is that when the battery in the chest strap wears down, it must be sent back to Polar for replacement. Wonder how long that will take and how much it will cost?