Nicholas Berkeley Mason, (born 27 January 1944) is an English drummer, best known as a founder member of the progressive rock band Pink Floyd. Mason is the only Pink Floyd member to have been featured on all of their studio albums, and the only constant member of the band since its formation in 1965. It is estimated that as of 2010, the group have sold over 250 million records worldwide. Mason co-wrote Pink Floyd compositions such as "Echoes", "Time", "Careful With That Axe, Eugene" and "One of These Days".