Talk about a study in contrasts. On the one hand, we have glam-metal stars Ratt and, on the other, the grunge pioneers who succeeded them in Nirvana. You'll get to decide who's inducted into the Ultimate Classic Rock Hall of Fame as the first round of this month's 100 percent fan-voted competition continues.

Ratt, of course, came first -- selling seven million albums in the U.S. alone between 1984-88, beginning with their triple-platinum debut 'Out of the Cellar.' The follow up, 1985's 'Invasion of Your Privacy,' sold another two million, followed a pair of platinum successes with 'Dancing Undercover' and 'Reach for the Sky.' Best known for the Top 40 hits 'Round and Round' and 'Lay It Down,' Ratt has shown remarkable chart resiliency -- even as members have come and gone. In fact, the group cracked the Top 40 once more with their most recent album, 2010's 'Infestation.'

Nirvana, meanwhile, saw a short but influential career lead to their induction into the Rock and Roll Hall of Fame earlier this year. Led by the late Kurt Cobain, the group's sophomore 1991 release 'Nevermind' has sold nearly 12 million copies -- reshaping the decade's popular music along the way. 'In Utero' went five-times platinum before Cobain tragically killed himself. By then, Nirvana's 1989 debut 'Bleach' was on its way to nearly two million in sales, as well.

So who makes it through to the next round, Ratt or Nirvana? You can vote once a day between now and Monday, Nov. 17, at 11:59PM ET. This month’s winner will be announced on Dec. 2. Be sure to read our official rules.