The 5080-0031 is the HP part code. This exhibit has been included as it looks like a valve and may or may not have originally been fitted with an IO base cap. It is in fact a gold plated quartz crystal. The operating frequency is 1.0 MHz and needs to be maintained at 71 °C for minimum drift.
This is no ordinary oscillator crystal and was most likely part of a 1950s frequency standard. Hewlett Packard were world leaders in this technology. The instrument company name from 1999 is now Agilent.
The quartz disc is in the centre.
The pinch and twisted wires for external connection.
The wide glass tube envelope is 28 mm in diameter and, excluding the base wires, is 55 mm tall.
Updated December24, 2019.