The thickness of the board beneath it gives deceptive scale. It’s about 50mm tall and the toroid is 85mm in diameter.
https://www.lcsc.com/datasheet/lcsc_datasheet_2408061709_Ruishen-RSCM11548-5mH-3P_C37634003.pdf
I was looking for much smaller CMCs. Also the datasheet for this part doesn’t have impedance-versus-frequency graphs so I refuse to buy it anyway :P
i would feed a hot metal stick into a U-shaped form, so it curls around the ring a few times, then cut it and let it cool and harden. they probably have a machine doing that.