6 kind of air distribution solution is optional. Bottom air return, or side air return. 2 pipes and 2 rows type as standard. 4 pipe is optional. Water valve inside is optional. contact us: Mr.John Sales Manager -------------------------------------------------- MECO,the Expert of FAN COIL UNIT Taizhou MECO Refrigeration Equipment Co.,Ltd www.china-fancoil.com Email:Johnding574@gmail.com