small compass or hidden message. MI9 purchased a number of signet rings from Regent Street jewelers that were used to conceal compasses. Modern tamper-proofing In modern use, seals are used to tamper-proof equipment. For example, to prevent gas and electricity meters from being interfered with to show lower chargeable readings, they may be sealed with a lead or plastic seal with a government marking, typically fixed to a wire that passes through part of the meter housing. The meter cannot be opened without cutting the wire or damaging the seal. Specially-made tamper-evident labels are available which are destroyed if the protected container or equipment is opened, functionally equivalent to a wax seal. They are used to protect things which must not be tampered with such as pharmaceuticals, equipment whose opening voids a manufacturer's warranty, etc. Figurative uses Seal of the Confessional Record sealing Approval The expression "seal of approval" refers to a formal approval, regardless whether it involves a seal or other external marking, by an authoritative person or institute. It is also part of the formal name of certain quality marks, such as: Good Housekeeping Seal of Approval of the Good Housekeeping Institute Good Netkeeping Seal of Approval See also Company seal Keeper of the seal King of Na gold seal, the first seal in Japan Knights Templar Seal used to validate documents approved by the order Manu propria Privy seal References Bibliography Accessible on Wikisource External links God's Regents on Earth: A Thousand Years of Byzantine Imperial Seals, from the Dumbarton Oaks Collection UK National Archives on seals Not All Online Authority Seals are Credible - Harvard's Ben Edelman says "Suppose users have seen a seal on dozens of sites that turn out to be legitimate. Dubious sites can present that same seal to encourage more users to buy, register, or download." Signet ring article - Berganza, London: Signets: Sealed with a Ring Search Results (database of Byzantine Seal impressions from Prosopography of the Byzantine World project (PBW) Photographic reproductions of medieval seals in the Lichtbildarchiv älterer Originalurkunden searchable via the verteillte Bildarchiv prometheus Authentication methods Rings (jewellery)