This is a Bravo Company Sling Swivel known as the QD, model BCM-QDSS-2.
This Heavy Duty Swivel features a Flush Plunger to prevent accidental release and Carbon Steel construction with a Manganese Phosphate finish.
Features:
For 1-1/4 Slings;Tumble Deburred and Sand Blasted Before Plating;Flush Plunger