The Ultraflex Shotgun Loop.

Based on the Ultraflex sling design and strap size, it provides the same benefits as the Ultraflex for carry positions. It attaches to a firearm without studs with a rubber restrictor strap which attaches to the stock, and unique para-cord loop system that securely attaches to the barrel by what is known as a "clinch knot". A great system for double barrel shotguns and over and under shotguns. It is designed for any firearm, shotgun, rifle, or muzzleloader that does not studs for swivel mounting. 

Specifications

    - Fits all firearms that to not have attachment centers
    - Multiple wearing positions
    - The most secure sling you will find
    - One size fits all, fully adjustable