Define
A real limit (time, units, seats, eligibility) that makes delay cost something.
Mechanism
Loss of option. The close is the disappearing chance, not a louder adjective. Fake scarcity is a different and worse pattern.
Verdict
The limit is true and the buyer already wants the thing.
Don't
The cap is theater, or the reader has not yet decided they want it. Urgency before desire is noise.
Copy skeleton
[OFFER restated] Only [N] [seats/units] · closes [DATE/TIME] · [timezone] [What disappears after] [ASK: do it now]
Gulf note
Ramadan, Eid, and National Day windows are real scarcity. Avoid only 2 left on an endless catalog. Gulf buyers name that lie out loud.
Rights-cleared examples
Advertising Letter and Sample Menus for The Wright Diner, 1929 (image 1)
Larkin Company Trade Catalog, 'My Larkin Clubs Earned These for Me' (cover)
Referral Reply Form Enclosed with Anderson Electric Car Company Letter to Clara Ford, 1915
Airmail Service Advertising Pamphlet, October 1918
Colonization Rooms Printed Circular, November 1, 1848
Book-of-the-Month Club Promotional Pamphlet (1926)
The New Salesmanship and How to Do Business