Seal (5e Equipment)
From D&D Wiki
Taking the appearance of elaborately designed markings and circles a seal is tattooed to the flesh using magical inks. A seal allows the owner to cast a cantrip or spell of 1st to 5th level without the expenditure of a spell slot. The owner must be able to cast magic and have the spells corresponding ability score requirement to utilize. A seal can be used once per day and the magic of the seal cannot be changed once made although permanent damage to the seal will prevent its usage. Finally, you may only have two seals at any one time.