Single Push Button QD Swivel 1.25"
These are the same Manganese Phosphate, made in the USA, swivels that come with the Tactical Intervention and Blue Force Gear slings.  These are also referred to as Flush Cup swivels, and require the corresponding female bushing.  They are packaged individually and include user instructions.  This QD swivel will work with most slings that are wider than 1". 
If you are ordering a TIS sling, you may include a set of QD swivels with your sling order.