Bd re sl 25gb 2x 10 pack spindle key features high capacity 25gb disc speeds 2x 10pk spindle hard coat protective layer excellent playback performance blu ray discs get their name from blue laser technology the shorter wavelength of the laser is the reason it is blue in colour the blue laser has a wavelength of 405nm compared with the wavelength of 650nm for dvd which utilises red laser technology the benefit of having a blue laser with a shorter wavelength means it is possible to wr