“Designed primarily for weighing letters in order to determine postage, this non-digital, non-electronic, and barely even mechanical little gizmo is nonetheless accurate enough that its use has been approved by the US Postal Service. Besides its role as a letter-weigher, the ‘Personal Post Office Scale’ has reportedly also found use in fields such as home brewing, field biology, cooking, and police work.” Read more / Order. Thanks, Rasmus.