Features:
       1) Lightweight, durable and balanced

        2) Reusable, high density and waterproof

        2) Matches contour of SC tire profile

Specs:   
Blue Insert             
Width: 1.5" (3.8cm)                                Inside  Diameter: 3.1"( 8.0cm)
Outside Diamter:4 " (10.6cm)                 Requires: Installation into tires

Description:
A firm insert is good because it supports the tire carcass better. The rc tire will not loose its shape in the corners and fold over itself.