The luminous flux from lamps is specified in lumens rather than candlepower. One "candlepower" unit is about 0.981 candela. The historical candlepower is equal to 0.981 candelas. In 1948, the international unit (SI) candela replaced candlepower. In modern usage, "candlepower" is sometimes used as a synonym for "candela". Each beam of light had an intensity of 30,000,000 candlepower. A given lamp has a higher candlepower rating if its light is more tightly focused. Initially the lighthouse had a brightness of 6000 candlepower and was visible for . The 1,400,000 candlepower light was replaced with a 3,000 candlepower light. The light output varied from 156,000 to 248,000 candlepower over many years. The first lantern available to the US Navy had 150 candlepower. The station is equipped with a 1,800,000 candlepower light visible for . In 1912 the candlepower of the light was increased from 27,000 to 80,000. One of the best-known of these was the English standard of candlepower. "Candlepower" is largely an obsolete term.