Emptyglass

2 clues
Refill indicator
Indicator that you need a refill
Similar answers:
Agateglass
Aglass
Artglass
Autoglass
Blownglassart
Brokenglass
Bulletproofglass
Carnivalglass
Carterglass
Cheapsunglasses
Clinkglasses
Cocktailglasses
Comingupempty
Copierglass
Cordialglass
Cutglass
Darkglasses
Darkglassestoavoid
Douglass
Douglasses