WWII German shell casing & clock

[ClarkB]

]Hello,
Today, I found an old German Kienzle vehicle clock mounted in the bottom of a WWII shell casing. The shell casing has an eagle over a swastika and the notation WaA406. There is also the mark IFH and a date 1938.
Curious to find out what else I can learn from these marks on the casing.

Thanks
ClarkB