Conditional formatting based on cell value and if value is found in a column

I need to create a conditional formatting based on the value of the current cell and if that value is found in a column.

Example.

Cell A1 has a value of 8am-4pm.

If that value is also anywhere in column B then the conditional formatting would apply.

Thanks for any help.

Nick

=isnumber(match(a1,$b$1:$b$100,))