Great product, the fit is perfect!
Works perfectly with the new Viridian RFX1
snug secure fit and grab around the belt. Don't have to worry about pulling your magazine and the holder coming with you.
Your Satisfaction, Our Priority: At Four Brothers Inc., customer satisfaction is at...
🔧 Don't forget Thread Locker — $1.50
Keep your holster hardware secure against vibration and loosening
✓ Added to your order!
$0.00 USD
FOUR BROTHERS HOLSTERS
Couldn't load pickup availability
Built for comfort, concealment, and adaptability. The 4BROS Springfield Armory Echelon RaceCar Appendix Rig is an IWB (Inside Waistband) appendix sidecar holster system designed specifically for Springfield Armory concealed carry pistols. Featuring adjustable sidecar spacing, a flexible injection-molded adapter system, and customizable ride height and cant adjustments, the RaceCar Appendix Rig is engineered to improve comfort, reduce printing, and provide a more natural fit for everyday concealed carry.
The 4BROS RaceCar Injection-Molded Appendix Adapter Plate is engineered to flex and articulate with the body's natural contours and movement. This flexibility helps reduce common pressure points associated with appendix carry while allowing the holster to conform more naturally against the body for enhanced concealment and long-term comfort.
Equipped with Discreet Carry Concepts 1 Series Overhooks and a Modwing concealment wing, the RaceCar Appendix Rig is designed to provide a secure connection to the belt while helping rotate the pistol grip closer to the body for improved concealment and reduced printing.
Information on the belt attachments used for the 4BROS RaceCar Appendix Rigs can be found through our Inside Waistband Attachments Blog article.
Unlike traditional fixed sidecar holsters that can feel rigid during daily carry, the RaceCar Appendix Rig utilizes a flexible 4BROS RaceCar Injection-Molded Appendix Adapter Plate that connects the holster and magazine carrier. This articulated design allows the system to flex naturally with the body while helping improve comfort, concealment, and mobility throughout daily movement, seated carry, and extended wear.
Information on available holster color options is available in our Holster Colors Guide.
View additional compatible appendix carry options in the 4BROS RaceCar Appendix Rig Collection.
Pistol Fitment: Each holster is precision-formed to the exact Springfield Armory Echelon pistol or pistol/light combination selected from the dropdown menu to ensure proper fit and retention.
Magazine Carrier: The included magazine carrier is matched to your selected firearm platform and features adjustable retention through a side-mounted tension screw.
Optics Compatibility: The holster profile is cut to clear most popular pistol-mounted red dot optics used on Springfield Armory pistols.
The 4BROS Springfield Armory Echelon RaceCar Appendix Rig is available for several popular Springfield Armory concealed carry and duty pistols. Each holster is precision-molded to the exact firearm or firearm and weapon light combination selected from the dropdown menu to ensure proper fit and retention.
Light-bearing RaceCar Appendix Rig models retain on the weapon-mounted light instead of the pistol frame. This allows consistent retention and repeatable indexing across supported firearm and light combinations.
Our preferred light option for Springfield Armory configurations using the Streamlight TLR-7 A or X is the TLR-7 X USB, part # 69455.
Our preferred light option for Springfield Armory configurations using the Streamlight TLR-7 HL-X is the TLR-7 HL-X USB, part # 69458.
The 4BROS Springfield Armory Echelon RaceCar Appendix Rig is proudly manufactured in Logansport, Indiana using premium materials, precision CNC-cut components, and purpose-built forming processes.
Pro Tip: Apply a removable thread locker to all hardware screws after final adjustment to help prevent loosening over time.
The RaceCar Appendix Rig is an IWB (Inside Waistband) sidecar-style appendix holster designed specifically for Springfield Armory Echelon pistols. It features adjustable spacing between the holster and magazine carrier for improved comfort, concealment, and customization.
Unlike fixed sidecar designs, the RaceCar Appendix Rig uses a flexible 4BROS RaceCar Injection-Molded Appendix Adapter Plate that allows the holster and magazine carrier to move naturally with the body. This improves comfort during movement, seated carry, and extended daily wear.
The RaceCar Appendix Rig supports several popular Springfield Armory Echelon pistols and weapon light combinations listed in the supported fitment section above. Each holster is custom-built for the selected configuration to ensure proper fit and retention.
For light-bearing configurations, retention is indexed on the weapon-mounted light. Non-light-bearing models retain directly on the firearm. Magazine retention is adjustable using the side-mounted tension screw.
Yes. Both the holster and magazine carrier feature adjustable cant and ride height. The spacing between the components is also adjustable to help optimize comfort and concealment.
Yes. The holster profile is designed to clear most popular pistol-mounted red dot optics commonly used on Springfield Armory pistols.
If your pistol or weapon light configuration is not shown, contact the 4BROS holster support team. Additional configurations may already be supported or under evaluation.
Please review our Four Brothers Holsters Exchange, Return and Refund Policy
Made in America. Founded, located, engineered, manufactured, and shipped from Northern Indiana.

Great product, the fit is perfect!
Works perfectly with the new Viridian RFX1
snug secure fit and grab around the belt. Don't have to worry about pulling your magazine and the holder coming with you.
Just unboxed and test fit. All the screws were already tight and all components feel quality. The kydex is thick and sturdy. Would buy again and plan on buying other products from this company.