Knock-off
A knock-off (often abbreviated to KO) is a reproduction of a toy produced without authorisation from the license-holder for that toy. In the case of Transformers, this means any transformers toy that is produced without authority from TakaraTomy or Hasbro.
These toys are often (though not always) of poorer manufacturing quality than the original versions. They are frequently produced to be sold cheaply, produced in different colours or even different sizes to the originals. Only occasionally do these knock-offs actually pretend to be authentic Transformers - some are produced to a manufacturing standard comparable to the originals, and can be easily confused with originals on the secondary market.
Opinion is divided amongst fans about the value of knock-off toys - some fans see them as providing the only means of affordably acquiring certain toy moulds, while other fans insist that this attitude is what prevents TakaraTomy and Hasbro from being able to produce authorised reissues.
Some Transformers toys known to have knock-off versions are:
