This is our Picatinny/Weaver Saiga-12 Shotgun Quad Rail System & Handguard Mount. The main part includes two sections attached by screws - an inner piece and the bottom piece which includes the side rails. The two included removable top rail sections can slide onto and attach securely to the inner piece. The top rails are 8.75" and 13" long. Made of high quality 6061-T6 aluminum and finished in Matte Black, it's both lightweight and durable.