Outdoor Unit	Indoor Unit	BTU Option
CU-4S27NKZ	CS-S9PKZW	9K BTU
CU-4S27NKZ	CS-S12PKZW	12K BTU
CU-4S27NKZ	CS-S18PKZW	18K BTU

Please note that warranty coverage is only limited to the following combination:​ 

Panasonic System 2  (2 Ticks)	Panasonic System 3 (2 Ticks)