one layer single row [put 1 pair of shoes]] three-layer single row [put 3 pairs of shoes]] three layers and two columns [put 6 pairs of shoes]] three layers and three columns [put 9 pairs of shoes]] three layers and four columns [12 pairs of shoes]] five-layer single row [put 5 pairs of shoes]] five layers and two columns [put 10 pairs of shoes]] five layers and three columns [put 15 pairs of shoes]] five layers and four columns [put 20 pairs of shoes]] six-layer single row [6 pairs of shoes]] six layers and two columns [put 12 pairs of shoes]] six layers and three columns [put 18 pairs of shoes]] six layers and four columns [put 24 pairs of shoes]]

one-piece installation-free