301, 301X, 301T are inner ALC Koto,
I usually switch between B2X and 301Z, the clearly different between them is 301Z has vibration like a 5 ply wood Korbel blade, B2X has no vibration at all(same no vibration as FZD ALC),
speed and spin in loop/topspin seem similar,
but smash 301Z is...