The main difference between this model and the earlier version is the switch from a Tone to the Filter control. The Filter cuts high frequencies as it is turned clockwise. The RAT logo was also switched from an all caps logo to one that was more stylized, while the “a” and “t” were now lower case.
text from Pro Co website
02/25/2017: ToneHome is looking for an Ibanez CS-505 narrow box first issue with flying fingers side graphic. Any hint is highly appreciated. Other than that we're looking for boxed effects or just boxes for Ibanez narrow box GE-601, AD-80, CP-835, OD-850. Please submit your offers or leads here: e-mail