Girl group APRIL attended a promotion event for Mobile Pop in Hongdae, a popular hangout region in Seoul, on March 13, 2016. The Kpop idols released a special winter album titled Snowman last December.
Mobile Pop is a prepaid shopping card (now available as mobile app if not mistaken) by GS Retail which runs a chain of convenient stores and supermarkets in Korea.
Source: Zetta (Kr)