ICHILLIN' has unveiled the scheduler for their upcoming 4th single album 'Challenger.'

According to this scheduler, which was released on March 13 KST, the girl group will reveal three sets of concept photos, followed by a music video teaser, then finally the music video release. Along with the scheduler, they also released album's tracklist, featuring title track "Alarm" and B-side "Siren."

Are you excited for 'Challenger'? The album will drop on March 23 at 6 PM KST.