Blu-ray is an optical disc format like CD and DVD. Blu-ray discs can hold more information than other optical media, because of the blue lasers that the disc drives use. A single Blu-ray disc can hold up to 25GB of data. Dual-layer Blu-ray discs will be able to store 50GB of data — equivalent to four hours of HD content. In 2010, the Blu-ray Disc Association (BDA) announced formal specifications for a new Blu-ray disc XL (BDXL) format that boasts a maximum storage capacity of 128GB.