Patent ID: 7635402

Claim:
An air filter status evaluator for a vehicle comprising: a housing having at least one sidewall; and a replaceable air filter member adjacent the at least one sidewall and positioned with an air stream passing through the air filter member, wherein a portion of the sidewall downstream of the replaceable air filter member is an air filter status indicator configured to provide a visually perceivable signal external of the housing that indicates if the air filter member requires replacement, wherein the air filter status indicator includes at least some contoured portions of sufficient size and shape to releasably hold at least a moveable portion of the sidewall in a first position corresponding to an acceptable air filter member status, and allowing manually reversible flexing movement of the portion of the sidewall to a second position corresponding to an air filter member status requiring replacement in response to air intake pressure differential with respect to atmospheric pressure being above a predetermined value on a downstream side of the air filter member.