Vang Comp Plus-1 extension. I will start and say that Vang Comp are great machinist. Being a Machinist myself I can see the quality. The extension is built like a tank, the stainless follower is also A+. Highly recommended! Here is a picture of the assembly, consisting of the extension, split ring, and sling mount. The far right of the picture is the factory 590 end cap for size reference. Here is a picture of it mounted on a 18.5 breacher barrel, it works perfect by staying just behind the muzzle break and still allowing to use the breacher.
