Less Freight: 2 Pack makes the freight less for each product.Blank Rack Panel Mount Size: W19" * H1.73" * D0.43"Material: Black Durable and will never rust,All Metal, Cold rolled steel.Vented Rack Panel Black: Vertical Screws fixed on the mounting rail,Good for Cabinets Rack Proper Airflow CirculationInstallation Spacer Functions: Rack Vented Panel Keeping dust and dirt out of your Internet data center cloud rack, Fits almost 19" Standard Server Rack or Network CabinetIf you need more support, Please feel free to contact us.They are shipped by Amazon (fast).