Features:

• Newest 5F891 Timex NAVMAN "3D" GPS Sensor
• Provides Distance, Pace and Speed Data
• No Calibration Necessary
• Elastic Strap and Belt Clip Included
• Works with all Timex Speed and Distance Models

Editor Reviews:

Product Description:
Digital Speed + Distance Sensor - Comes with one 'AA' Battery, For all Timex Ironman* Triathlon® and Speed + Distance watches, Provides distance, pace and speed data in Metric or English readings, Altitude, elevation, latitude, longitude, ascent and descent data, No calibration required

Rating : - Works flawlessly!
I'm using this in conjuntion with my Timex 5F001 HRM watch and the Data Recorder 2. No problems at all. Took less than three minutes for it to get an initial signal and about one minute for it to find the signal at each power-up.

My watch picks up the signal up to three feet away from the device.

No problems at all with using it. It's a recommended addition to the Bodylink system.