This is a part to a plastic injection mold called a side action, slide action or cam action depending on who you speak to. It is only the back half of the assembly which has the angled hole for the cam pin to actuate it and the angled backside where the wedge locks it when the mold is closed. The front half would bolt to it and contain the molding area. The x on the sides and bottom are grease grooves meant to retain grease to lubricate the block as it slides between the gibs. It is made most likely of a heat treated tool steel. It looks from the pics to be a quality one. Either made by a high end mold shop itself or maybe even by a company that specializes in mold components that mold builders use to speed up and simplify the mold building process. The engravings on the block would refer to a tool number, asset number, or finished part number. If it is a prefabricated slide it may even be the stock number for that size slide. An example of an omni system is linked. They specialize in the prefab type units. The part you have is the piece all the way to the left in the picture of the set.

This is a part to a plastic injection mold called a side action, slide action or cam action depending on who you speak to. It is only the back half of the assembly which has the angled hole for the cam pin to actuate it and the angled backside where the wedge locks it when the mold is closed. The front half would bolt to it and contain the molding area. The x on the sides and bottom are grease grooves meant to retain grease to lubricate the block as it slides between the gibs. It is made most likely of a heat treated tool steel. It looks from the pics to be a quality one. Either made by a high end mold shop itself or maybe even by a company that specializes in mold components that mold builders use to speed up and simplify the mold building process. The engravings on the block would refer to a tool number, asset number, or finished part number. If it is a prefabricated slide it may even be the stock number for that size slide. An example of an omni system is linked. They specialize in the prefab type units. The part you have is the piece all the way to the left in the picture of the set.

References:

http://www.omnimold.com/slide-assemblies/Uni-Slide.htm