D Tuning, also called One Step Lower, Whole Step Down, Full Step or D Standard, is an alternate tuning for guitar. Each string is lowered by a whole tone or two semitones resulting in D-G-C-F-A-D. It is used mostly by heavy metal bands to achieve a heavier, deeper sound and by blues guitarists, who use it to accommodate string bending.
Some bands who used this tuning on a six string guitar: