Restriction indicator device for filter assembly

A filter element comprising:

• a filter media;
• and
• a restriction indicator device comprising an attachment portion and a movable portion, the attachment portion attachable to a portion of the filter element, the movable portion movable relative to the attachment portion between a non-buckled position and a buckled position,
• the movable portion moving from the non-buckled position to the buckled position once a predetermined pressure drop between an upstream side and a downstream side of the movable portion of the restriction indicator device is met,
• wherein the movable portion comprises a first movable pair and a second movable pair that each comprise a radially inner portion and a radially outer portion, wherein each radially inner portion is thicker than the corresponding radially outer portion;
• and
• wherein each radially inner portion is a wall portion and each radially outer portion is a hinge portion.