APM has decided to no longer produce these lens in cell and has also discontinued the full doublet refractor.
If interested I would contact TS to see if they have a adapter ring for your specific tube. If not you will have to hire a mill shop to make one.
This is a outstanding upgrade in optical quality at a low price. These last ones use FPL-51+LaF-53 lanthanum, older series (like mine) used FK-61+LaF-53 and it is outstanding.
https://www.teleskop-express.de/shop/pr ... -cell.html