Laylax shows how to install the First Factory MP5 Picatinny Stock Base made for the Tokyo Marui MP5 NGRS series... "It is a stock base with a picatinny rail of Tokyo Marui next generation MP5 A5. By installing this product, you can install our company's 'Railstock Pipe Adapter Light' and 'Folding Railstock'. The stock position can be adjusted to any position on the Picatinny rail, allowing you to customize your style. It also has a hole for the QD sling swivel to achieve a high degree of freedom in sling work."