The Odin Works ARCA rail was designed to give you the flexibility and ease of use that you need for mounting your rifle. This rail system is commonly used for mounting Arca Swiss style tri-pods but it also can be used with Arca Swiss style bi-pods too, making tri-pods and bi-pods easy to switch back and forth between. We've all been there, having to take off a bi-pod mount and switch to a tri-pod mount at the most inconvenient time. Now, the ARCA rail system is your all in one solution to mounting your rifle, no hassles guaranteed. The ARCA Rail allows for Arca Swiss quick release attachments, and depending on your needs you can pick either the 4" or the 9" rail. Many shooters use the 9" rail so they can be mounted by tri-pod at the base of their forend against the mag well, and also have a bi-pod attached on the furthest end closest to the muzzle. The 4" rail is a great solution for if you have other accessories and attachments on your rail and need to take up m...