Rounded corners Tool-less mounting clips included 19" EIA compliant Made in the USA Limited Lifetime Warranty The Kendall Howard 4U Flat Spacer Blanks are a cut above the rest. Spacer Blanks are often used as a way to fill in any gaps and conceal empty rack spaces in a rack or enclosure. The use of filler panels not only makes racks look neat, clean, and organized, but when installed properly they provide added support to the mounting rails. These rack panels are also critical for controlling proper airflow especially in cold aisle/hot aisle applications. Universal/Tool-less Mounting - The 4U panel features oblong mounting holes that are compatible with any standard rack hardware. However, the included tool-less clips make installation a breeze with any universal cage nut style rail. Rounded Corners - The rounded corners and durable powder coat finish provide a smooth, safe edge for safe handling and installation. Proper Airflow - Using spacer blanks to fill the gaps and openings throughout your rack installation is especially important when thermal management is a concern. Not only will the filler panels prevent unwanted debris, such as dust, from getting in, but it will also prevent hot air from being recirculated into your equipment. Professional Look - Installing rack panels in the unused rack mount spaces (RMS) gives your overall installation a clean and organized appearance.