Both the single and its music video were released on February 13th.
While the album is categorized as a digital single, limited physical copies, called Promo CDs or Promo Albums, were made. These CDs are given to broadcasting staff on music and radio shows to help promote the single. However, they are usually sold to Korean eBay sellers, who then sell them at high prices due to their rarity. Promo CDs are often but not always autographed, and can be distinguished by a sticker that says "비매", or "Not for sale", and/or the phone number of the entertainment company.
The phyiscal version of So Wonderful, while very rare, is more common than LADIES' CODE's other digital single, Hate You, because it was performed on both music and radio shows. The Promo CD was also given away by Soompi on Lee.Bahl.Show's radio broadcast.
A So Wonderful slogan was also available on the LADIES' CODE Daum Cafe for a limited time.
→ see So Wonderful/Gallery