This is a set of HPI 24mm Red - Medium/Soft Pro Molded Insert Tire Foams.
Designed specifically for HPI's Racing Slick 24mm tires, these Pro Molded
Inner Foams in "mid-width" 24mm size are the ideal match! The three
different compounds of inner foam allow racers to fine-tune the
tire/insert combination for better results. These new inserts are
color-coded for easy identification.
Racers should start out with the same tire/insert combination front and
rear, and if they need less steering they can try a firmer insert in
the front tires, or a softer insert in the rear tires. If the racer
needs more steering, they can try a softer insert in the front or a
firmer insert in the rear.