GrovTec US 12 Pack Black Spacers Black. These sling swivel studs are designed to allow the user to attach accessories such as slings and bipods to their firearms. These studs provide a solid platform which will enhance accuracy and your shooting pleasure. made in specialized factories Specifications for GrovTec US 12 Pack White Spacers: Manufacturer: GrovTec US Condition: New Package Contents: GrovTec US 12 Pack White Spacers GrovTec US GTHM65: 12 Pack Black Spacers Black