The TPRO 1/8 Off Road inserts fit 100% to the tire cross-section of the TPRO tires, but also very well for all other brands.
The foam inserts are produced in Taiwan with special shapes, in the hardnesses soft (green), medium (blue) and hard (yellow).
The quality control also ensures constant Shore hardnesses. The glued TPRO tires are produced with a blue insert.