Low reserve indicator for a coreless paper towel dispenser

A paper towel dispenser contains an upright roll of paper towels having an inner periphery from which the towels are dispensed. A low-reserve indicator mechanism is affixed to the housing within the chamber for indicating when a remaining quantity of towels in the roll is low. The indicator mechanism includes a sign mounted for movement between a retracted position and an indicating position for displaying indicia through a transparent portion of the housing when the roll is low. The indicator mechanism also includes a release mechanism supported upon an upper end of the roll and movable downwardly in response to becoming unsupported by a diminishing radial thickness of the roll to cause the indicator to move to its indicating position. The indicator mechanism automatically confirms to rolls of varying height and outer diameter.