What's the 2009 GMC Sierra door speakers size?

The 2009 GMC Sierra haS6.33" door speakers. You can install aftermarket speakers in it, but You will need to reuse the factory bracket. Using the pick tool, remove the plastic trim pieces from behind the interior door handle and the pull handle. There is two 10-millimeter hex head bolts that need to be removed behind the door pull and one behind the handle. Now remove the door lock lever, if the lever is in the unlocked position You will notice a small square on the side of it, use the pick tool to remove it and then slide the latch up and off. Next remove the triangular sail panel which is just inside the door panel next to the mirror. There are three clips behind it that hold it in, be careful when pulling it off so You don't break any of the clips. If You have automatic locks You have to remove the cover from it it'll pop right off and there will be two 10-millimeter hex head bolts that need to be removed from there also. Now work around the outer perimeter of the door panel and pry it off to release the clips. Once the door panel is off remove the Bolt holding the speaker in.