"OF CTC Tea" likely refers to a specific grade and processing method of tea, but "OF" is not a standard grading term in the context of tea.
In the context of tea grading, "OF" typically stands for "Orange Fannings." Fannings are small leaf particles that result from the processing of tea leaves. They are smaller than Broken Orange Pekoe (BOP) or Broken Pekoe (BP) grades.
However, "OF" is not commonly used in conjunction with "CTC." CTC usually refers to the Crush, Tear, Curl method of processing tea leaves, which results in small pellets.
So, it's possible that there might be a specific regional or industry-specific context where "OF CTC Tea" has a particular meaning, but without further context, it's difficult to provide a precise interpretation.