The different SumoSprings colors identify their density. SumoSprings come in three different densities: -40, -47, and -54. Blue SumoSprings are -40, black SumoSprings are -47, and yellow SumoSprings are -54.
Light and medium duty applications
Blue -40 density captures more air in the millions of micro-cellular bubbles, creating an air spring suitable for light and medium duty applications.
Light, medium, and heavy duty applications
Black -47 density balances the amount of urethane and air bubbles to create an air spring suitable for light, medium, and heavy duty applications.
Medium and heavy duty applications
Yellow -54 density traps a smaller amount of air in the air spaces creating a stronger air spring suitable for medium and heavy duty applications.