What size factory speakers come in a 2004 Chevrolet Silverado single cab truck?

What size factory speakers come in a 2004 Chevrolet Silverado single cab truck? I have blown my speakers and want to buy some new ones to replace them. I can't find my book that came with the truck and have been unable to find the info online. I just need to know what size they are. I am guessing to sets of 4X6 speakers but am not sure. Can anyone find the specs online?|||check www.crutchfield.com if you go to car speakers and select your truck it will say what fits and where.