It is a category to post copyright free BGM music material of the genre of hard rock. Hard rock is a genre that mainly distorts the guitar sound with distortion, etc. and features a sound that emphasizes deep bass, and is considered to be a blend of blues and rock by the Beatles and Jimi Hendrix. Major bands include Red Zeppelin, Deep Purple, Guns & Roses, etc. If you are looking for free hard rock music, you can find it here.