Who know what speakers sizes are for a 2003 chevy avalanche 1500?

[grul]

I've read that 6 3/4 but that size doesn't exist on ebay and how many speakers it has.??
How can i know if i have the boss or onstar? i know i need 6 1/2 but i think it has tweeters also but on the door. how many speaker it has on each door??

 

[wishmaster]

With Bose system or Without Bose but with Onstar

Front speakers
Dash: Tweeter
Front Door: 6-3/4

Rear speakers
Rear Door: 6-3/4

If no Bose system and no Onstar you lose the tweeters.