Company name is given as "Frederick Post, A Teledyne Company"

The 1969 School Drafting Supplies Catalog contains only an incomplete listing of Post slide rules available at the time  ("Write for catalog of complete POST slide rules, including pocket versions") but it does include the first known mentions of projection models 1447DP, 1450DP and 1460DP.

Lavender cell color indicates a model that Post was probably selling in 1969 but didn't mention in this catalog.  White cell color indicates a model that was specifically mentioned in this catalog.