IEC 60297-3-109:2015 specifies dimensions and physical properties of chassis and associated printed boards in order to provide mechanical and environmental integrity for embedded computing devices. They are used in various applications such as machine control, medical, transportation, aerospace and telecommunication, typically based on single board computers. For the easy definition of the suitable chassis and associated single board dimensions, this standard is based on a structural grid of 44,45 mm (1,75 in).Key words: Dimensions, Mechanical Structures, Chassis, Embedded Computing Devices