This is a Allen Sling known as the Baktrak Glen Eagle, model 8342.
The BAKTRAK(R) Glen Eagle Rifle Sling comes with a soft molded back for Extreme Grip that also reduces sling related noise with its rubber tread grip back. Features 1.25" heavy duty webbing" a thumb loop" and swivels tested to 300 pounds.
Features:
1.25 heavy duty webbing;Swivels tested to 300 pounds