Wilson Combat Ultima-Lube II is a blend of petroleum and synthetic lubricants specially formulated to insure optimal performance of any firearm and inhibit wear. The unique blend of lubricating fluids has proven ideal for today's high-tech semi-auto weapons, whether manufactured of conventional steels, aluminum alloys or stainless steel. In addition, we have found nothing superior to Ultima-Lube II for the proper lubrication and protection of the hand-fit custom firearms that Wilson Combat is known for.