Abstract: A composite material usable for producing gaskets, the composite material being composed of a perforated metal core sheet sandwiched between facing layers having sealing properties and compression-laminated thereto. The core sheet is provided with a uniform array of square holes, each bordered by a set of four triangular tangs whose apex portions are flared outwardly with respect to the hole, the tang sets from alternate holes projecting from one side of the core sheet and the tang sets from the other holes projecting from the other side thereof. When the sandwich is subjected to compression, the tang sets on opposite sides of the core sheet then pierce the related layers and are caused to bend downwardly and thereby clinch the layers to the core sheets whereby the tang sets are then being embedded within the layers, each tang set affording an omnidirectional holding force.