A DIN rail is a metal rail of a standard type widely used for mounting circuit breakers and industrial control equipment inside equipment racks. These products are typically made from cold rolled carbon steel sheet with a zinc-plated and chromated bright surface finish. The term derives from the original specifications having been published by Deutsches Institut für Normung (DIN) in Germany, which have since been adopted as European (EN) and international (ISO) standards.

The three major types:

1，Top hat section, type O, or type Ω, with hat-shaped cross section.
2，C section
3，G section

Top hat rail EN 50022

This 35-mm wide rail is widely used to mount circuit breakers. The EN 50022 standard specifies both a 7.5 mm (shown above) and a 15 mm high version, which are officially designated

top hat rail EN 50022 – 35 × 7.5
top hat rail EN 50022 – 35 × 15
Some manufacturers catalogues also use the terms Top hat section / Type O / Type Omega (Ω).[citation needed]

C sectionThe rails are symmetrical within the tolerances given. There are four popular C section rail, C20, C30, C40 and C50. The number suffix corresponds to the overall vertical length of the rail.

G sectionG-type DIN rail (according to EN 50035, BS 5825, DIN 46277-1).