The name “Roy Ehrhardt” has become a synonym for detailed, reliable bedrock historical information about pocket watches worldwide. His ingenious Ehrhardt American (EA) Numbered Drawings have served to clarify the identity of American-made pocket watch movements for generations of horologists. Mr. Ehrhardt’s collection of numbered drawings serve horologists as nautical charts serve oceanographers, or as John James Audubon’s drawings serve ornithologists. Each field of study would be archaic, inaccurate, and hopelessly chaotic without these tools.

In Roy Ehrhardt’s Identification and Price Guide to American Pocket Watches the EA Numbered Drawings are referenced in alphabetical listings containing detailed descriptions of every American-made pocket watch in its various models and grades that Roy Ehrhardt has cataloged. The descriptions are coded to allow concise, consistent presentations of accurate information across all American manufacturers regardless of the various manufacturers’ hyperbole or jargon.