The MS4 Sling is a Dual-QD version of the standard MS3 Sling. With Push-Button QD Sling Swivels in place of the standard Paraclips, the MS4 provides a two-to-one point convertible sling option compatible with front and rear QD Attachment Points.
AR-15, Issue:11, Page:070
Big Book Catalog, Issue:72, Page:252
Sinclair, Issue:5B, Page:219