What makes Vibrato by Stellar notable?

'Vibrato' marked a significant commercial moment for Stellar, as it debuted at number 6 on the Gaon Album Chart, reflecting their rising popularity in the competitive K-pop landscape. The title track also garnered attention for its catchy melody and choreography, helping to solidify the group's presence in the industry. Released on July 20, 2015, 'Vibrato' was Stellar's second extended play, following their debut EP 'Marionette'. At this point in their career, the group was refining their sound and image, aiming to build on the initial success they garnered with previous releases.