All corrugated metal hose and hose assemblies are manufactured according to ISO13080
ECF 01.0, 01.1, ECF 01.2

An extra flexible metal hose (so called closed pitch) has extra flexibility and increased fatique life.
It’s used with braiding to manufacture metal hoses for industrial use.
ECF 02.0, ECF 02.1, ECF 02.2

A standard flexible metal hose (so called standard pitch) has standard flexibility.
It is used to manufacture heat exchangers, metal hoses for industrial use. It is well-suited for multiple bending.
ECF 03.0, ECF 03.1

A minimum flexible metal hose (so called open pitch) has minimal flexibility.
It is used to manufacture heat exchangers. It is well-suited for one-way bending, not designed for cyclic loads.