Selling M4 S system upper set. This is a complete upper. I have parts to make the furniture tan. The upper on top is metal, in the slide forward design, the one on bottom is a TM style "pop up" receiver, and so will work for either type. Comes with rails, Black and Tan furniture, spare gas tube and barrel mounting bracket. This is a unique design and makes for a great look. Buyer pays shipping, PayPal only. Price firm, selling as single unit. Will part Buttstock: $10 Grip: $10 Plastic Upper Receiver: $25 Metal Upper Receiver: $35 Black Rail Segment: $35 Tan Rail Segment: $25 Rail segments come with rail mounts and screws necessary for mounting. Tan handguard paint is peeling. Gas tube and mounting bracket will be thrown in for free