ESLI describes an indicator that indicates the end of service life. The ESLI might be a component incorporated into the mechanical assembly, yet it might likewise allude to attributes that show that a device is harmed somehow or another. It indicates how long filters can be utilized before they should be changed. Some respirator cartridges have ESLIs to assist a client with deciding when to change. An end of service life indicator (ESLI) is a framework utilized for breathing apparatuses to alert the wearer that the oxygen or air level is reaching its lower limits.