What size speakers are in the factory 1989 GMC Sierra SLE.?

[lcplvanderkleed]

Im talking about the factory speakers like in the rear and front i have a standard cab stepside so all in all it has 2 speakers up front and 2 in the rear. Im looking to replace them with upgraded speakers but dont know the size. thanks.

 

[bigboro718]

4x6 no biger front & back are the same so good luck alpine have a pr $70 so dose infinty

 

[G-998709]

What's the size for the dashboard speakers in that same Gmc