Samson F.R.B. Rails - 4 inches Forward Rail Bracket. R.B. Forward Rail Bracket threads into M4 and M16 handguards. This Rail Bracket by Samson is perfect for mounting accessories. We also carrie Samson Quick Flip SC for Aimpoint 3X Magnifier Mount Samson Quick Flip Mounting Plate - Standard M4 and Extended Samson Star-4 AR Pistol Free Floating Rail Samson Star Carbine Length Free Floating Rail for AR-15 Samson Drop-In-Rail System and other. For a full line of Samson Tactical Accessory and other products by Samson on sale please visit Samson page on our web site. For more brand name rifle scope mounts rings and bases please visit our Rifle Scope mounts accessory store section. Samson F.R.B. rails available models: FRB-4: Samson F.R.B. Rails - 4 inches Forward Rail Bracket FRB-4-5: Samson Forward Rail Bracket - 4.5 inches Forward Rail Bracket Package Contents: Samson Forward Rail Bracket F.R.B. Specifications for Samson F.R.B. Rails 4" and 4.5" Forward Rail Bracket: Application: Shooting Accessory Samson 04-06018-01: F.R.B. Rails - 4 inches Forward Rail Bracket