This specification gives the requirements for copper-clad Invar material for use in the fabrication of metal-clad laminated sheets, used for printed boards. The use of copper-clad Invar material in printed boards modifies some properties of the boards, for example thermal capacity and coefficient of thermal expansion. This specification covers copper-clad Invar material of nominal thickness from 0,1 mm to 2,4 mm. It applies mainly to copper-clad Invar material supplied in rolls, but by agreement between purchaser and supplier it may be applied to copper-clad Invar material produced in sheets.