The Bobbin Material is BLACK ALUMINIUM, Short for BASV
The 4'' Size Coil
The Winding Material is High Grade Copper Wire, TOTOKU Brand
The Taping Paper is White Spunlace Cloth
With Vent Holes
4Layers Coil
The Lead Wire is Copper Pad, 4PCS,
Widely Used in Car Subwoofer and other High Power Speaher.