Watches for Android phones:

Our core functionality is supported on all Android Wear watches. Here is some information about a few of the more popular ones:

Watch GPS Heart Rate Price Range REFSIX Core Functionality [1] REFSIX Performance Tracking [2]
Polar M600 Yes Yes Medium Yes Yes
Sony Smartwatch 3 Yes No Low Yes Yes
Moto 360 Sport Yes Yes Medium Yes Yes
Fossil Q Founders No No Medium Yes No
 

Watches for iPhones:

Watch GPS Heart Rate Price Range REFSIX Core Functionality [1] REFSIX Performance Tracking [2]
Apple Watch Series 2 Yes Yes High Yes Yes
Apple Watch Series 1 No Yes Medium Yes No
 

[1] Core feature includes recording all match details and incidents. Access to basic statistics that are not related to physical performance i.e. average numbers of cards given.

[2] Performance tracking feature coming soon. It will provide detailed analysis of referee positioning on the pitch during the match and requires the watch to have GPS