Rail Interface Systems (RIS) or Rail Accessory Systems (RAS) are synonymous with each other but reference to what is the picatinny rail system. They are standardized segments of ridges and slots that allow mounting options by clamping onto the rails and secured together with its slots. It was developed as an answer to those looking for a modular system to adapt and change a weapon's configuration quickly and easily to different combat scenarios. They allow for the attachment of a variety of accessories including scopes, sights, sling and points to name a few and can be constantly reconfigured with ease.
