For use in trucks up to 7 pounds. For trucks over 7 pounds, or if you prefer a standard drive feel, please use the Halo Foam chart to help choose the right foam for your application. 
 
Available in AirDown, Mid AirDown, and Ultra AirDown, the Halo AirDown series foams deliver a very soft drive feel and allow the tire to wrap around rocks while maintaining good vertical and side-hill integrity.
 
Unique Waterproof and flow through 2 stage foam insert design with a waterproof closed cell inner ring for exceptional side-hill control, and a unique outer waterproof and flow through web like foam for exceptional drive feel. 
Use Halo WebWrap foams with 1.9 name brand tires such as Voodoo, Pitbull, ProLine, RC4WD, and others. 
The AirDown series is designed for 4.5-4.8" tires, it is not recommended for 4.19 tires.