Class 1 Oxygen Minder is a warning system for your new or existing vehicles which provides an attention getting LED display for an "at-a-glance" update of existing oxygen supply levels. The Oxygen Minder display provides a visual warning at 25% oxygen remaining and at 20% an audible alarm sounds to let you know that your oxygen has reached a critically low level. The audible alarm can be manually silenced but the visual warning will continue to flash until the oxygen is replenished.