DEL Pool Ozone Generators have ozone-resistant, PVC tubing inside and out. For outside tubing, use this green exterior/outside tubing which is ordered by the foot.
7-0594 Ozone Supply Tubing is:
Compared to the standard style clear PVC tubing 7-0075, the 7-0594 tubing has a higher durometer which means you can make bends in the tubing without it kinking up.
When purchasing 7-0594 replacement Ozone Supply Tubing, you may also need a new Ozone Supply Check Valve (current part number 7-1140-07). Get both in one great kit: