As you can see from the above picture this little accessory called Extreme Rear Support System (E.R.S.S.) looks like a bipod but it is placed instead of a rear bean bag. And if you look closer, then you’ll see that it is not quite a bipod. So this product is purposely designed to be used instead of the rear support bag. It is made by a company called Rugged Ridge Outdoor Gear.
The E.R.S.S. has four leg angle options. In order to adjust it to the needed angle, you have to press the button located near the pivot point and move the legs until they click into the position. In different positions, it has a different top V-notch or cradle angle and of course different heights. I think before purchasing this accessory, you’d better make sure that it fits the width of your rifle’s stock at its highest position, where the V-notch is the narrowest.
E.R.S.S. is machined from a solid block of aluminum and has polymer inserts in cradle and feet areas. It is also very lightweight weighing only 4.4 oz. The MSRP of this accessory is $125. The price also includes a belt pouch which it comes with.
Here is a video showing how this accessory works:
Despite the good features of this product, I think the rear bags may still have an advantage over it. When using a rear support bag, you basically have infinite position adjustability within its minimum and maximum limits. I mean you can squeeze the bag to get the exact elevation of the rifle that you need for any particular shot. In the case of this device, you have only four positions and heights and a bit more adjustability by sliding it back and forth.