This is the Ernie Ball 4601 Black Finish Super Strap Lock.
The Ernie Ball Super Lock is from nickel plated steel. You get a complete 360 degree secure connection. Robust mechanics provide maximum durability.
Each pack includes a set of 2 Super Locks, and includes all hardware needed for installation. The Super Lock uses a pilot hole of: 7/64" Diameter, 1 1/2" Deep