I have two panels whose overall dimensions are 24"x 48"x 7.5". The absorbing material is 6" thick. I bought these several years ago and don't remember the brand, though i am pretty sure they are GIK. There are no markings. I do remember that I chose them because they were the lowest frequency panels offered.
I am asking $25 for the two of them. Mostly I need to move them out of my living room.
These are local pickup only. I live in the Santa Cruz, CA area.