In general there are three types of Royal Seals, in Thai called Phra Rachalanjakon, i.e. the Royal Seal, the Privy Seal, and the Great Seal.

The ones on display here are the royal seals of King Prajadhipok, with the largest one being the Privy Seal, which has this King's royal emblem (fig.), that is known as Prajadhipok Saktitejana.