Hello, yes it's a 12'' ESS woofers
https://www.ebay.fr/itm/Paire-d-enceintes-vintage-1973-ESS-AMT-Heil-1/234275446784?hash=item368be7a000:g:K2cAAOSwzMZhiBDj&pageci=64e3dafa-3ca7-4279-a7f5-3e43a1d4920f&redirect=mobile
Cordially yours
Gilbert
https://www.ebay.fr/itm/Paire-d-enceintes-vintage-1973-ESS-AMT-Heil-1/234275446784?hash=item368be7a000:g:K2cAAOSwzMZhiBDj&pageci=64e3dafa-3ca7-4279-a7f5-3e43a1d4920f&redirect=mobile
Cordially yours
Gilbert