Coral filters are general purpose warming filters which come in increasing amounts of color temperature correction as the number in the series increases. They are commonly used to produce slightly "orangey" skies.
The graduated resin filters in this set measure 4 x 6" (100 x 150mm) x 2mm thick. The 6" length allows for adjustment of the filter within the holder.
Lee Coral Filter Color Temperature Conversion Chart
These color temperature filters convert 5500 degrees Kelvin to the value shown below:
Coral 2: 4255 degrees (Kelvin)
Coral 4: 3774 degrees (Kelvin)
Coral 6: 3390 degrees (Kelvin