Notes: "1) Plastic Polyphase Duplex 2) Case has the name Henry A. Ravenscroft 3) This rule was given to me on April 20, 2019 by Richard Lyon 4) 57 years before I attended an engineering class taught by Mr. Ravenscroft at Santa Rosa Junior College 5) The words ""Petaluma California"" also show on the case 6) See Mr. Ravenscroft's obituary included"
