Tretorn Permanent Pressure balls have the same pressure as atmospheric air. Unlike pressurised balls, which get their bounce from internal pressurised gas, Permanent Pressure balls have the bounce built into the rubber core. The vital secret of Tretorn Permanent Pressure balls lies in the chemically engineered rubber core, which is constructed of a blend of carefully selected raw materials, various rubbers, and chemical ingredients.
The built-in chemical dynamics of these secret rubber compounds give Tretorn Permanent Pressure balls superior playability and feel. Unlike pressurised balls, which have a relatively short lifespan, Tretorn Permanent Pressure balls have a life-time bounce guarantee.
The Plus is Tretorn's most responsive Permanent Pressure tennis ball. It is an extra long lasting tournament ball for all players