Abstract: An electro-magnetic induction heater has a heating coil which defines a throat through which a metal strip (moving towards a plastics film laminating station) passes thereby to be heated to a laminating temperature. The coil turns are flexible, and are braced at spaced positions in braces which are mounted for movement towards and away from the metal strip. Each brace has an associated adjustment means. The positions of the respective braces are adjusted during heating, preferably automatically, so as to adapt the coil throat shape to the varying cross section (and/or other characteristics) of the strip to be heated, thereby to ensure uniform temperature distribution across the width of the strip. Under automatic control each adjustment means is operated in closed loop manner by associated actuating means in response to deviation from a reference level of a sensed temperature signal provided by an associated sensor positioned adjacent the emergent heated strip.