Kel Tec RFB Quad Rail Black. The two scalloped cut-outs on the top of the Picatinny allow the shooter freedom to adjust the gas system if needed and allow the ejected casings to leave the ejection port. The shooter should take caution on which accessories to mount on the left hand side of the weapon since this could block the ejection port. Includes : (1) RFB-420 Quad Rail (1) Locking Nut & Wrench (1) Set screw with Hex Key Specifications for Kel Tec RFB Quad Rail Black RFB-420: Manufacturer: Kel-Tec Color: Black Fabric/Material: 6061-T6 Aluminum Package Contents: Kel Tec RFB Quad Rail Black RFB-420 The Kel Tec RFB Quad Rail Black RFB-420 is a quality addition to the Kel-Tec lineup. For more great deals on Gun Parts by Kel-Tec please browse our Kel Tec Gun Parts page. Kel Tec RFB Quad Rail Black