Metal. Free Standing Shoe Racks: This Boot Rack is perfect for 4 pairs Boots in different shape, such as for Tall Knee-High, Hiking, Riding, Rain or Work Boots. Prevent Creases: With the design of inverted storage and round top fits boots perfectly, the boot rack keeps boot shafts straight, prevents debris and dust from falling into the boot, help prevent wrinkles and creases, while allowing them to air dry. Space Saving: Standing boot rack/shoe rack holds up to 4 pairs of shoes or boots while conserving storage space. Easy to Install: Easy and quick to set up by following the installation instructions. There're no sharp edges, just units snap into place step by step with simple tools. Fit More Occasion You Need: The shoe rack organizer can be used in different parts of your home such as the hallway, the bedroom, the garage, the entryways, the closet, the patio outdoor, ect.