Available in three sizes; simply measure the height, width, and depth (the distance your unit protrudes outwards from your window) of your window-mounted air conditioning unit and select a size larger than your measurements:
Small - 15"H x 21"W x 16"D (Fits Most 3,000 - 7,000 BTU Units) (ASIN: B074QYWQ7G | UPC: 653020948632)