Conn. Gen. Stat. § 42a-2A-204: Firm offers.

An offer by a merchant to enter into a lease contract made in an authenticated record that by its terms gives assurance that the offer will be held open is not revocable for lack of consideration during the time stated. If a time is not stated, the offer is irrevocable for a reasonable time not exceeding ninety days. A term of assurance in a record supplied by the offeree is ineffective unless the term is conspicuous.