Another mystery part, what do you think this is?

simple high current terminal block

high power 50 ohm load

high power capacitor for induction heater

oven assembly for precision oscillator


Answer: High power capacitor for induction heater (0.66uF, 600V, 300A, made in France by Celem)



The people who answered it right were:

W1KF
K3MK
PA3DFR
WP3EX
YB7KNV, Jimmy
Duane N. McOlin
buckstar

Thanks to everyone who gave it a try.