I bought the Nike + Sensor as part of a package with the Nike + Sports Band.

Before buying it, I had not realised that you had this sensor, and that it had to go in your shoe. I was then made aware that Nike make special Nike + trainers, with a built in area underneath the underlay in the shoe, where you can clip the sensor in.

I was worried I would need to buy a new pair of shoes for something I had only paid £35 for! Fortunately, after a little internet research, I found that you can buy little pouches that you can attach to your laces on your trainers, that can house the sensor, without the need for new trainers. The pouch cost me £7.99, and does the trick!

The sensor works from a mixture of GPS and Pedometer technology.

Combined with the Sports Band or the iPod technology, it measures how far you have run, the time taken, time per mile, calories burned etc. It calculates this according to your height and weight, which you input via your computer when setting up your Sports Band/iPod feature.

I find the distance calculations fairly accurate. On a route that I know to be 2 miles exactly, it calculates between 2 miles and 2.2 miles, depending on how fast I run. I think the faster you run, the more the sensor bounces, and it may think you have gone a little farther than you have. However, this may not be as bad if using the Nike + trainers, instead of the pouch on the laces.

All in all, it's a great way of getting a good idea of how far you have run and how many calories you have burnt, and it's good for keeping time so that you can see how well you have progressed over time.

After your run, you can also upload your run data to your computer and keep a log of everything, and set yourself goals, such as "run 100 miles in the next three months" etc.

Highly recommended.