In reading these forums, I see posts with test results that include FC values like 14.2, 17, 21, but my Taylor test kit comparator gauge is similar to this one (not my photo):
It only goes up to 5, unless I'm reading it wrong. So, assuming I'm reading it correctly, how do people measure these high FC values? One reason for asking is so I know if I've reached a shock FC level when that is necessary.

It only goes up to 5, unless I'm reading it wrong. So, assuming I'm reading it correctly, how do people measure these high FC values? One reason for asking is so I know if I've reached a shock FC level when that is necessary.