Chimney Caps are sized by adding the measurement of two adjacent sides. 
For example the north profile and the west profile:
 
Code           Material     Dimensions     Price

CCC16-4     Copper      Up to 4'           $  700
CCC16-5     Copper               5'           $  790
CCC16-6     Copper               6'           $  890
CCC16-7     Copper               7'           $  990
CCC16-8     Copper               8'           $ 1100
CCC16-9     Copper               9'           $ 1240
CCC16-10   Copper             10'           $ 1390
 
*Requires protective crate and freight shipping