C.R. Snelgrove Co.I have two of these temperature controlled crystal ovens which are designed to operate from a 6-12volt supply. They have standard 8pin octal bases and are manufactured from copper. Toronto Ontario, Canada. The firm was taken over and became the Frequency Control Division of Leigh Instruments Ltd in Ottawa.
These are two of several items given to me by Deborah Waters, which belonged to her late father.
Internal view showing the the crystals and the internal cover.