Exceptionally good core. Everything complies with the description. The ribbon is very brittle and has high resistance, which indicates amorphous/nanocrystalline alloy. The dimensions of the core (w/o the casing) are 39.5*24.5*15 mm. With the casing these are 44*21.5*19 mm. The ribbon is 30 micrometers thick. Probably 1K107 alloy.
Good product quick shipping.