The size is entered in decimals so that you have the option to search for a particular size. Centimeters are
entered normally, decimal and all.
Let's say you're seeking a work between 10 to 14 inches high and around 12 to 15 inches wide. You would then enter a 10 in the minimum height box and a 14 in the maximum height box. Then enter a 12 in the minimum width box and 15 in the maximum width box and click Start Search. You would leave the depth box blank.
A size of 23 1/2" x 40 1/4" x 12 3/4" would be entered 23.50 x 40.25 x 12.75