What is the importance of the "copper sheet" in the novel, Thirst No. 1: The Last Vampire, Black Blood, Red Dice?

The copper sheet is one of the primary supplies Arturo uses in his transformations. Sita lies on a copper sheet in Andy's basement when she tries to transform herself back into a human. The copper sheets is the conductor in the transformations, along with the vial of vampire blood, a crystal and a light source.