The LPSNx was developed as an improvement to the previous quad rail. This rail was inspired by lots of beneficial features that shooters have requested and demanded from Phase 5 and other manufacturers. The slender design, longer nose, ease of installation and superior construction are some of the features that we designed into this system. The LPSNx undergoes a rigorous extra de-burring process to ensure a smoother, snag free finish. The details and level of care during the manufacturing of the LPSNx make it the perfect choice for your Carbine or Rifle build. Specifications for Phase 5 Weapon Systems Inc LPSNx Free Float Quad Rail: Manufacturer: Phase 5 Weapon Systems Inc Color: Black Finish: Type III Hard Anodized Mil-Spec Fabric/Material: 6061-T6 Aluminum Gun Make: AR Platform Gun Type: Rifle Handguard Style: Quad Rail Gun Rail: M-LOK Inner Diameter: 1.35 in Outer Diameter: 2.25 in Mount Type: M-LOK Features of Phase 5 Weapon Systems Inc LPSNx Free Float Quad Rail: Integrated MLOK slots (bottom) for added mounting options Built-in QD Mounts with internal stops 6061-T6 Aluminum 1/2 inch sight distance increase for improved accuracy Light weight for improved mobility Package Contents: Phase 5 Weapon Systems Inc LPSNx Free Float Quad Rail Barrel Nut Hardware