This choke with an initial inductance of 8.5 µH contains a ring core with an outside diameter of 58 mm made from High-Flux material. It is used in a SMPS of 28 V / 140 A.
The typical slope of the saturation profile of this core is very easy to discern. However, because this core material is very expensive, an optimal economic solution requires that the operational point at rated current lies beneath the level of initial inductance.