Abstract: The present invention regards a fin for a finned pack for heat exchangers, including a plate in which a plurality of through holes is formed for the positioning of tubes intended to convey a first heat exchange fluid, the plate having an edge as well as two main faces, each intended to be licked by a second heat exchange fluid in a crossing direction (A-A) from an inlet portion to an outlet portion of the edge of the plate.

Abstract: The present invention is an element (1) for making a surface extraction replica (50) of a metallic material to be analysed (C), comprising a layer (2) suited to be placed in contact with a surface area (20) of the material to be analysed (C) so as to memorize the characteristics of the material to be analysed (C); the layer (2) comprises indium (In) or indium oxide (In203). The invention includes also a kit comprising a casing and an element for making a surface extraction replica, a method for making a surface extraction replica (50) of a metallic material to be analysed (C) and the use of indium (In) or indium oxide (In203) in a method for making a surface extraction replica (50) of a metallic material to be analysed (C).