Great news for Tennessee Titans linebacker Avery Williamson -- his 9/11 tribute cleats just sold at auction for $6,600 ... and it's all going toward a charity to help U.S. soldiers!
TMZ Sports broke the story ... Williamson customized his Nikes to honor the victims and first responders -- with patriotic symbols and the words "Never Forget" written on the back.
After he wore them in the game, Williamson put the cleats up for auction on CharityBuzz.com to raise money for Operation Warrior Wishes.
FYI -- the winner ain't just gettin' the cleats. The auction winner gets 2 tickets to a Tennessee Titans home game ... as well as an opportunity to chill with Avery.