As with all racing safety equipment, Head and Neck Restraint (HNR) fitment is critically important, and the Head and Neck Restraint user can increase the risk of injury if they are not fitted properly.  A Frontal Head and Neck Restraint (HNR) restrains the driver’s head relative to the torso during a frontal impact, thereby reducing the loads to the head and neck.

There are different types of HNR systems approved, two of them being the NecksGen™ REV™ and REV2 LITE™ systems.  Please refer to the general Head and Neck Restraint sizing chart below for proper fitment of the NecksGen™ REV™ and REV 2LITE™ systems.    

This system sizing chart is for ADULT NecksGen™ Head and Neck Systems.  Please note that according to the factory, YOUTH drivers CAN use the SMALL REV™ unit if the racing seat DOES NOT interfere with the device.  

If you need a Head and Neck Restraint system outside of this chart range, please contact our Technical Sales staff for other brand options that may be available for you.  

Properly Measuring Fitment for a NecksGen™ REV™ & REV2 LITE Head and Neck Restraint Systems


Locate a cloth tape measure and record the following body measurement:

  • A - Neck Diameter - Measure DIAMETER across the front neck line just above the collar while keeping the tape taunt. 

The NecksGen™ REV™ and REV 2LITE Head and Neck Restraint Systems come in several sizes as shown in the fitment chart below.    

Remember, if you DO NOT find a Head and Neck Restraint System that suits you or fits you properly, please contact one of our Technical Sales Specialist and they will work with you to find a solution for you.

NecksGen™ REV™ System - Head & Neck Restraint Sizing and Fitment Chart***
Factory Device Size
- Neck Diameter (in.)
3" to 5"
4" to 6"
5" to 7"

NecksGen™ REV2 LITE System - Head & Neck Restraint Sizing and Fitment Chart***
Factory Device Size
- Neck Diameter (in.)
4" to 5.5" 
Factory Tip:  If you wear a Small-Medium T-Shirt,
This is the size you want.
5" to 6.5"
Factory Tip: If you wear a Large-Extra Large T-Shirt, 
This is the size you want.


NecksGen™ offers two (2) different models - The original REV™ HNR system and the new REV2 LITE™ model.

NECKSGEN™ REV™ - The original REV™ system offers all the standard safety features as mandated by the SFI® 38.1 Certification Standard.

NECKSGEN™ REV2 LITE™ - The latest system, the REV2 LITE™ offers all of features of the standard REV™ model, but now also includes Adjustable Tethers, Rubber Grip Friction Pads, Higher Belts Guides and improved Shoulder Padding for increased driver comfort.  Best of all, the REV2 LITE™ unit is even lighter and weighs-in at just 1.2lbs.

A SIDE NOTE ABOUT SEAT ANGLE -  Many other HNR devices require a special HNR unit depending on racing seat angle.  The NecksGen™ REV™ and REV2 LITE™ are designed to work with ANY TYPE of seat angle. The drawing below shows all typical racing seat angles that all of the NecksGen™ HNR systems will easily accommodate.

NecksGen™ HNR Systems - Model Applications for Head & Neck Restraint Systems***
Seat Angle
Typical Racing Application
Applicable NecksGen™ Model
Jr. Dragster - Micro-Sprints - Mini-Wedge - Quarter Midgets
 NecksGen™ REV
(Use Size Small for Youths)


Adult Size NecksGen™ Systems Work with All Types of Race Cars and Various Seat Configurations including Sprint Cars - East Coast Modifieds - Asphalt Late-Models - Dirt Late-Models - Street Stocks - Legends - IMCA/UMP/Wissota Modifieds - Full-Bodied Drag Cars and Dragsters - Sedan Sportscars - Drag Boats - Open Wheel/Road Race Cars including Formula Ford®, Formula Mazda®, Barber Dodge® and Infiniti® Pro
NecksGen™ REV™

 NecksGen™ REV2 LITE™

TECHNICAL CREDIT AND ACKNOWLEDGEMENT: The above HNR, seat and helmet technical information and illustrations were compiled using excerpts from the Federal Internationale De L'Automobile (FIA) 'Guide and Installation Specifications for FHR Devices in Racing Competition' document published in June 2017.  To review this full PDF document click here or visit the FIA website Safety Section at (both links open new browser window).

Racecar Engineering™ Has All of Your Racing Safety Gear Needs Covered

Please remember that Racecar Engineering™ carries a full assortment of all NecksGen™ Systems.  On top of that, we also have in stock and ready to ship, over twenty (20) brands of safety equipment ranging from racing suits, driving gloves and shoes, underwear, hoods, socks, helmets, harness pads, seat belt restraints, helmet skirts, gear storage bags and much more.

Browse our wide selection of safety products and buy online today.  If you have questions about choosing the right safety equipment for your motorsports segment, please contact one of our Technical Sales Associates for assistance.

At Racecar Engineering™ we make every attempt to be every racer's 'One-Stop Safety Shop'.

Return To:  Main Technical Center Page  |  Head and Neck Restraint Info/Sizing Chart Page - All Brands

Related Tech Safety Topics:  Racing Helmets | Racing Suits | Driving Gloves | Driving Shoes | Racing Seats

*** HEAD & NECK RESTRAINT SYSTEM SIZING/FITMENT CHART DISCLAIMER: This head and neck restraint system sizing/fitment chart has been created by Racecar Engineering™ for our customer's reference and ease-of-use using the latest fitment information available from the factory.  Please always refer to the factory website, factory printed materials and factory personnel advice for the latest head and neck restraint system information about their brand of safety product.  The NecksGen factory website can be accessed directly at (link opens new page) - Racecar Engineering™ is not responsible for any typographical errors contained in this head and neck restraint system sizing chart/fitment material or the end-user's failure to verify & follow factory fitment specifications.