The Timex Road Trainer uses a chest strap sensor for maximum accuracy. The wrist monitor is a full-featured Timex Ironman sports watch. You can view your heart rate with the time of day and while using the chronograph and timer. It has a minimum and maximum heart rate alert, five pre-set heart rate zones and a customizable zone. I like the large number display and a night light. Perhaps because I've used Ironman watches in the past, I find the Timex more intuitive and I find it easier to navigate the displays and menus than I do with Polar heart rate monitor products. The watch is large, but you could easily wear it and use it as a sports watch, independent of its heart rate monitor function.
This is the base-model for Polar heart rate monitors. Polar FT1 heart rate monitor lets you set a manual target heart rate zone with visual and audible alarm. It gives you your average heart rate during your exercise and elapsed exercise time. I like the basic models for their ease of use, you don't have to remember which button to use for which function. You can also wear it as a watch - it displays the time and date. The extra large digits are appreciated. It has a backlight for viewing after dark. Water resistant up to 30 meters (100 feet).
Chest strap or no chest strap? It's your choice with the Sportline Duo. It comes with a chest strap heart monitor, or you can take your pulse at any time by placing two fingers on the plates on either side of the face of the watch. The watch allows you to set upper and lower heart rate limits and shows you time in zone, above zone and below zone. You get a continuous display of your heart rate and the percentage of maximum. On top of this, it is a full-featured sports watch with backlight, chronometer, interval timer, and built-in pedometer to estimate distance.
This Polar is a step up from the FT1 and FT2, as it includes calorie calorie expenditure and a more graphical display of your heart rate. It will also calculate your heart zone automatically based on your age. It saves and displays 10 workouts rather than the single workout shown by the basic models, plus your ongoing totals.It also has watch functions for time of day and date. But it does not include sports watch features such as a stopwatch or countdown timer, splits, etc. such as you find in Timex models.
This simple heart rate monitor allows you to set target zone limits with upper and lower alarms. Its features include a calendar, time display, and daily alarm. It has a large LCD display with a super-glow light that is easy to read. It has a user-changeable battery and comes with a 3-year warranty.