How to read Streng loupe serial number

When you Loupe was manufactured ?

Four or five digit serial number on the neck plate with no letters, 1954 – 1963. Serial number on neckplate starts with an L, 1963 – 1965. Big F on the neckplate with a six digit serial, 1965 – 1976. Serial number starts with 

Why should we care about coral?

• Millions of special fish live in coral reefs
• Coral reefs are the most biodiverse ecosystems on the planet
• Entire countries were created by coral reefs
• Endangered species depend on coral reefs
• Coral reefs act as a first line of defense against storm surges, flooding, and coastal
  erosion
• Coral reefs contribute billions of dollars to the global economy through tourism