Everclear is a brand name of an American company Luxco (formerly David Sherman corporation) for a rectified grain spirit.
It is bottled at 151-proof (75.5% ABV) and 190-proof (95% ABV) strengths.
Colorless, flavorless and lacking any distinctive aroma, the primary use of Everclear is to increase the alcoholic level of a cocktail without diluting much the other ingredients. Its high flammability also makes it useful for certain types of flaming drinks.