A method and unit for heat-shrinking overwrappings of heat-shrink plastic material of a succession of products; an orderly succession of products is conveyed by conveying means; each product is subjected to a first heat-shrink operation along the conveying means and by means of a first heat-shrink device; and each product is subjected to a second heat-shrink operation along the conveying means and by means of a second heat-shrink device separate and at a distance from the first heat-shrink device.