Legal vs approved rubbers - What is the difference ?

[Camel Glue]

So what is the difference between legal and approved rubbers ?

[Satsuky]

In the context of rubbers , you cannot use the word "legal" to all rubbers, though it is OK to use it in the context of other rules such as an illegal serve

However the distinction between "legal" & "approved" comes in only for rubbers that are boosted or spein glued

Spein gluing in NOT ITTF approved . Boosting also is NOT ITTF approved per Rule 2.4.7 & Regulation 3.4.2.2
However spein gluing & boosting are also illegal under common laws of almost any country because it violates health code laws'
Spein gluing & boosting could also become criminal if serious health issues such as (lung) cancer or (brain) tumor develops not only to the offending player due to first hand effects but second hand effect upon other players or officials or spectators or their families present.

ITTF has been trying to hoodwink the IOC & pips players lately by claiming that spin gluing is just a performance issue & nothing to do with health.
And ITTF has done an excellent job of fooling the IOC & the idiot choppers with this diversion tactic