Checking Interior Dimension: To properly install, Checking the minimum cabinet opening width and minimum interior depth. Each order is One Single set. item dimensions D* W* H : 21 x (A) x 3 inch A has 8 sizes of Width (Overall width are 12'' , 15'', 18'', 21'', 24'', 27'', 30'', 33'') **OVERALL WIDTH = Drawer box width plus 1" which the Thickness of drawer slide. for example: ROT30, the width of the drawer box is actually 26’’, and the thickness of the rails on both sides is 1’’. After…