Jim Weir wrote in
:

Indeed the West Bend basic timer is a model of simplicity.
In 1985 I bought two of them. I modified one of them for
Rutan's Voyager as a fuel tank alarm device and put the
other one in my 182.

I don't actually have one of these, but I have read (on the
internet, so it must be true!!) that these have a slight design
flaw, and the timing depends on voltage, so as the battery goes
down the timing slows down.

--
Regards,

Stan