A flexible circuit is a vast accumulation of conductors bonded to a thin dielectric, or insulating film. Silver or Copper may be used for conductivity

SILVER FLEX CIRCUIT
unique features

Single Sided
Double Sided (Thru-Hole)
Heat Stabilized Polyester
Embedded SMD (LEDs)
Carbon Overcoat
Printed Resistors

COPPER FLEX CIRCUIT
unique features

Single and Double Sided
Polyimide or Polyester
Tin, Nickel, Gold Plating