Is OX same as hardbat ?

[Ama Nana]

It is not clear to me if hardbat is same as what they refer to as OX or if they are the same
Are they both legal in table tennis

[Melbournite]

All hardbat is OX but not all OX is hardbat.
Both hardbat & OX rubbers are approved for ITTF use.

OX means a pips out rubber of any type without sponge, short, medium, long or super pips.

Hardbat is the first rubber in table tennis before sponge arrived in 1952

A hardbat racket by definition has (traditional) OX short pips on both sides (or one side if other is unused as in a penhold)

[arender]

Hardbat players do not consider a racket with OX short pips on side and OX short pips as a hardbat racket.
In fact use of any long pips is considered dirty by hardbat players.

[Kyle 49]

I am not sure if hardbat is even legal anymore ?