The Sealed in Christ Collection is about bearing an impression. If your heart is soft and ready to hear the sacrificial story, like melted wax it would take the impression of the cross, and like a letter be sealed.
A seal bears a distinctive mark, which stands for the person who owns it. Seals were used as a mark of authenticity, of genuineness, an official design used as a signature, to guarantee and secure the contents. The nature of the seal was to confirm truth, to certify as being accurate, exact, of said size, quality and capacity. When sealed, the item was settled finally and irrevocably.
How gracious of our Lord to mark us with His Seal, forever & finally securing our salvation in this world and our inheritance into God's family in eternity.