What is GTG?

[avalanche5678]

Hi, I know little about monitors. I found the monitor I want to buy in my price range. I see one that is 3ms response time and one that is 3ms(GTG) for a $100 more. What does that gtg mean? THanks

 

[rexter]

http://peripherals.about.com/od/computertermglossary/g/graytograydefin.htm