This line of NavePoint shelves is designed with flexibility in mind. The depth can be adjusted from 18 to 29 inches. It has slotted venting to reduce the possibility of overheating. Made of high quality cold rolled steel with a powder coated finish that protects them from rust and corrosion. Assembly required. Please note that this shelf has a surface area of 16.81" x 17.75", which is fixed. The mounting rails can be adjusted from 17.75 inches to 29.19 inches.