noun
two star attractions; two leading actors; two main features
Originally from theater, now used broadly for any pair of standout people, items, or selling points that define a group, event, or product.
このチームの二枚看板は、エースピッチャーと四番打者だ。
The two star players of this team are the ace pitcher and the cleanup hitter.
新商品の二枚看板は、軽さとバッテリーの持ちだ。
The two main selling points of the new product are its light weight and long battery life.