Description: The Allen-Bradley/Rockwell Automation 1756-A7 chassis is a small and compact chassis that is made for the Allen-Bradley ControlLogix systems. This chassis is one of the smallest ControlLogix chassis that is available and it has only 2 mounting tabs on the top and only 2 mounting tabs on the bottom. The 1756-A7 chassis can be installed with or without 2 SEM screws, but if it is installed without the SEM screws, then it needs 2 star washers in addition to 2 flat washers and 2 split-lock washers. Additionally, this chassis needs 4 Phillips screws if it does not have SEM screws, but it only needs 2 Phillips screws if it is used with SEM screws. The 1756-A7 chassis is open equipment which does not have an enclosure for protection.