The installation on the IMSBig tank required modification.
I said I couldn't install it, but I was able to install it by modifying the Tank side.
I bought this product because it is compatible with the IMSBig tank made after 2007. However, it was not a simple installation.
Both ZETA Cap and Tank had no problem with 7mm Screw Pitch.
The problem was the inside diameter; the ZETA Cap was 64mm and the Tank was 65mm, so it wouldn't go in.
I managed to install it by grinding 1mm of Screw mountain on Tank side with #60 Sandpaper.
I am very happy with the texture of the Cap, but I had to process the expensive Big tank to no avail, so I gave it an overall satisfaction rating of 3.


