‘DIN Rail’ comes from the German DIN standard, for standardised metal bracket forms and the enclosures mounting to them.  DIN rail is commonly used in electrical applications, in fuse boxes, or larger IoT or control applications.  The widest used DIN rail is the 35mm top-hat profile, which all CamdenBoss DIN enclosures can mount to (CNMB, CIME, CVB and CMEB products).