Mossberg 590 sling mount. Many competing products are manufactured from insubstantial stamped sheet metal and have rather sharp edges that not only can cut the sling, but can cut the operator as well. The sling swivels are machined in our facility from AS-35 Geneva steel. Of exceptionally high quality, this famous Swiss steel features molecular structure with elongated grains for added toughness. The corners have been rounded and dehorned for the operator's safety. A ball bearing detent on the Sling Attachment helps secure the unit behind the magazine tubes end cap. Both versions are manganese phosphated matte black per mil-spec.