Samsung AC KNZDCH/AA Series Installation Manual page 9

Return air requirements
Typical Closet Installations
Upflow Accessory Filter Box Kit
NOTE
Accessory Air Filter Box for 1" or 2" Air Filters. Filter Size Adjustment knob is on both sides.
FILTER BASE ASSEMBLY KIT MODEL NUMBERS - FIELD INSTALLED, PURCHASED SEPARATELY
Closet Wall
ADJUSTMENT KNOB ADJUSTMENT KNOB
FOR 1" OR 2" FILTER FOR 1" OR 2" FILTER
9