Help identifying tweeters


May anybody help me identify this tweeter? It has a hexagon base, 4 1/4-inch outer diameter. Thanks.

https://www.thegearpage.net/board/index.php?media/unknown-tweeter-1.195338/
https://www.thegearpage.net/board/index.php?media/unknown-tweeter-2.195337/
thrustmag
Try at DIYaudio.

Also, if it's ferrofluid you may just need to clean it and replace.
Thanks to Wolf_teeth at DIYaudio forum for identifying this speaker as  a SEAS hexadym design.
That's right. Thanks, Eric. You made it happen.