ESS Speaker AMT HEIL Ribbon Replacement Diaphragm AMT, 689-1109 ESS AMT Speaker HEIL Ribbon Diaphragm Part # 689-1109 Original factory ESS Part Hand folded, USA made Size: 1-1/4" x 2-15/16" (32mm x 75mm) Impedance: 4 ohm, DCR: 3.7 ohm