The Name Says it All! PIAA's Intense White bulbs produce a more radiant white beam without any hint of blue. This bulb has been re-engineered from the ground up. What you will see in the H4 type bulbs is a larger-than-standard glass tube with a white tip coat. The larger glass tube increases output (28% whiter color than Star White Technology) and allows the bulb to burn at much cooler temperatures. PIAA's new Intense White Bulbs provide the best possible balance between performance and bulb life.
H4 = referred to as a 9003 / HB2
9004 = referred to as an HB1
9005 = referred to as an HB3
9006 = referred to as an HB4
9007 = referred to as an HB5