DFCO Quick Stop QD Sling Cup / Barricade Stop Black. The QUICK STOP is here to get it done... quick. It has a natural anti-rotational property and when paired with our D-NUTs becomes Q-Sert handguard compatible. Specifications for DFCO Quick Stop QD Sling Cup / Barricade Stop: Manufacturer: DFCO Color: Black Fabric/Material: Steel Finish: Melonite QPQ Mount: M-LOK Base/Mount Type: Side Mount Features of DFCO Quick Stop QD Sling Cup / Barricade Stop: M-LOK Compatible Package Contents: DFCO Quick Stop QD Sling Cup / Barricade Stop DFCO QUICK-STOP-BLK: Quick Stop QD Sling Cup / Barricade Stop Black