The rail and the terminals it carries
"DIN rail" almost always refers to the standard 35mm top-hat profile rail (defined under EN 60715) that carries terminal blocks, relays, circuit breakers and other control-panel components in a consistent, tool-free mounting system. Terminal blocks snap onto the rail in a row to form a terminal strip — but a functioning, tidy terminal strip needs more than just the terminals themselves, which is where the accessory range comes in.
What the common accessories actually do
End stops (or end brackets) clamp at both ends of a terminal row to stop the blocks sliding along the rail under vibration — a strip without them will eventually work loose. End plates and partition plates separate and insulate adjacent terminal groups, particularly important where different voltage levels sit on the same rail run. Jumpers (or cross-connectors) link adjacent terminals electrically without separate wiring, commonly used to distribute a common supply or ground across several points. Marking systems — pre-printed or field-writable tags that clip onto each terminal — are what turn a wired panel into one that can actually be maintained and traced years later.
Specifying accessories for a panel build
Accessories generally have to match the terminal block series they're paired with — end stops, partition plates and jumpers are sized and profiled for a specific terminal width and manufacturer range, not universal across brands. When specifying a panel build or a replacement terminal strip, list accessories against the exact terminal block series in use rather than assuming compatibility across ranges.