Louver 101. As you know, a louver is a relatively common tool that can be used for a variety of applications – most often in airflow or ventilation applications. But it is not always known that louvers can easily be created in your punch press, versus with a die-set. We receive many requests for samples of different types and sizes of louvers – and the variety is nearly endless. The images here show a grouping of three- sided cut louvers and a grouping of single-sided cut louvers.