This is a 34.4 mm  8 ohm tweeters diaphragm 

• Voice Coil dimension :34.4  mm 
• Dome: Titanium
• Impedance:8 ohm
• CCAR
• Height (Dome):6.2 mm
• Overall dimension :62 mm
• Terminal distance:72 mm

Voice coil :

• Copper Clad Aluminium Wire ,flat wire