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Product Overview

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HTP® XOS-H® in M-LOK - New for Fall 2023 - Now offering a High Temp Polymer (HTP) injection molded version of our G10 machined XOS-H RailScales. HTP XOS-H scales are a 3-sided solution that provide more than twice as much grip surface in a similar mounting footprint to our traditional HTP Scales. Adding a 135º wing on each side of the panel allows for the HTP XOS to tightly wrap your rail, and provides one seamless grip area for unparalleled handling and heat protection. This variation of our traditional G10 XOS Scales offer the same great features, but add an accessory cutout that partners seamlessly with other RailScales products to give you multiple modular options that best fit your shooting style. While most commonly used at the 6 o’clock position with our Karve, Karve-P, Anchor, or RSB, the XOS-H will also fit our QDX sling mount as well as additional future RailScales products to mount at various positions based on use. They are available in 4 popular industry colors: Black, Flat Dark Earth, Sniper Grey and OD Green. These are sold individually, and will allow you to outfit your firearm with even more added texture, grip and heat protection at a reduced cost. These will accommodate most popular M-LOK handguard rail systems, however please check the specs below to insure these will fit yours.

New HTP IR Material (NIR): Our HTP scales are heat stabilized and utilize 50% long glass fiber for high strength and and high rigidity properties. High HDT of 500º due to crystalline properties and glass loading. This also makes the HTP scales very isotropic to minimize warpage, the material is even suitable as a substitute for die cast metal parts. The new HTP XOS-H scales also feature a new Near-Infrared compliant upgrade to our material (NIR). The HTP NIR material was originally formulated for a recent military contract and we decided to carry it over to our commercial line of products as well. The IR additive absorbs Short Wave IR radiation (non-visible light), yet prevents the emission of longer wave IR radiation (visible light).  These properties make the material they are added to virtually invisible when viewed using night vision / FLIR equipment. Look for the “NIR” marking on the back of our HTP line. The new HTP NIR will be coming to the rest of our HTP product line by the end of 2024.

The XOS-H cutout slot is compatible with these RailScales products.

The XOS-H cutout slot is compatible with SureFire Scout Light Pro lights (w/ M-LOK mount) with end-user modification. Send an email to for modification instructions. 

Ships Free and Made in USA

  • Quantity: Sold Individually
  • Mount Type: M-LOK
  • Footprint: 3.5-Slots
  • Length: 5.520"
  • Width: 1.150"
  • Thickness: 0.125"
  • Weight: 0.55oz w/ hardware
  • Material: HTP® NIR™ (Injection Molded Glass Filled High Temp Polymer)
  • Color: Black, FDE Tan, Sniper Grey, OD Green
  • Hardware: US Made 416 Stainless M-LOK Nuts
  • Fastener: US Made T20 Torx Fasteners w/ Nylon Thread Patch

Fitment Info - Fits rails with mounting flats of 0.678" or narrower including the following:

  • Bootleg Inc. CamLok
  • Dakota Tactical HK Series MLOK
  • Daniel Defense Slim
  • Daniel Defense MFR MLOK - DOES NOT fit the MFR XL Rail.
  • Fortis Night Rail
  • Geissele 4-Sided Rails (Mk4*, Mk8)
  • Geissele MK16 (URG-I)
  • HK Parts HK Rails
  • Hodge/FN Wedgelock
  • KNS Bren 805
  • Midwest SSK/SSM
  • Midwest G3KL/G3ML
  • Midwest Gen 2 Extended AK MLOK
  • Parker Mountain Machine Scar Bottom Rail
  • PWS Mod 1/Mod 2
  • Sig Sauer Canebrake SD 
  • Sig Sauer MCX-SPEAR LT - Only fits at 6 o'clock, DOES NOT fit at 3 or 9 o'clock.
  • Sig Sauer MCX Virtus SD 
  • Vltor Freedom

Does not fit:

  • Brownells BRN-180
  • Black Rain Ordnance MLOK
  • Daniel Defense RIS III 
  • Larue 2.0 Stealth MLOK 
  • Noveske NSR, NHR, NSRM
  • Radian Model 1
  • Radical Firearms MLOK 
  • Sig Sauer M400 MLOK/Tread
  • Sig Sauer M400 X-Series SDI
  • Sig Sauer MCX Rattler Non-SD
  • Sig Sauer MCX-SPEAR (308)
  • Sig Sauer MCX Virtus Non-SD
  • SOLGW Wedge Lock MLOK
  • SOLGW M89/L89 MLOK
  • TriArc TriLok MLOK 



© 2024 RailScales LLC All rights reserved. RailScales®, HTP®, XOS®, XOS-H®,  XOS-W™, HTP NIR™ are registered trademarks of RailScales LLC.

For all patents and trademarks, see


(3 reviews) Write a Review

3 Reviews Hide Reviews Show Reviews

  • 5
    Best rail covers out there

    Posted by Alex M on Mar 2nd 2024

    These are probably hands down the best rail covers I’ve bought. I do think they are pricier side but their quality definitely beats out everybody’s. Already have 3 of my AR’s decked out with them.

  • 5
    HTP XOS-H mlok

    Posted by Jeremy on Jan 31st 2024

    Great fit and finish the mlok screws have thread locker on them make sure you read the directions you can over TQ them and can crack.

  • 5
    Great quality!

    Posted by Jimmie Meadows Jr on Nov 16th 2023

    Fit is as you would expect , pairs flawlessly with the Anchor . Make sure you have enough rail space for it in conjunction before order. Highly recommend , can’t bet the style and function .