No universal uniqueness requirement applies. The actual knowledge must meet the applicable specialized-knowledge standard.
Explain depth without exaggeration
Identify relevant experience and contributions supported by records. Saying nobody else could ever learn the work may be inaccurate and does not replace a substantive explanation. Hypothetical example: a superconducting-magnet supplier wants to transfer the specialist who maintains its calibration sequence.
Name the specialized knowledge in operational terms, then identify the record that proves both its company-specific character and the employee’s familiarity. Training logs, controlled manuals, project histories and access records are more useful than a title alone. Sequence the analysis from entity relationship, to foreign employment dates, to knowledge, to the U.S.
duties that need it. Cases falter when the description merely recites advanced skill shared by many workers in the industry. The employee must have the qualifying foreign period within the lookback, and the proposed assignment cannot be ordinary labour supplied to a customer.
Plan around the five-year L-1B limit. Keep the knowledge description specific enough that a reviewer can distinguish it from familiar industry practice without exposing unnecessary confidential material.