Abstract: Disclosed herein is a method and apparatus for monitoring the air pressure of a tire. Various colors are displayed by the apparatus to denote an inflation level of the tire, and the apparatus may remain coupled to the air nozzle of a tire indefinitely. The apparatus may include a diaphragm that deforms in response to an air pressure differential on opposing sides thereof. Deformation of the diaphragm may alter the position of a color indicating cup, such that a color is displayed through an observation window, informing a user as to the inflation state of the tire. Further provided is a method for monitoring tire pressure in high pressure tires.