Is there any reason why the new locking ends cant be used with the OG cast acrylic tubes.
Yes the locking functionality wont work but will they still create a watertight seal?
Hi @Yeti591, welcome to the forum 
From the technical details sections on our product pages:
- the piston diameter of the 4" Locking Flange is 103.95 ± 0.05mm
- the inner diameter of our old 4" Cast Acrylic Tubes is 101.19 ± 0.3mm
Accordingly, a locking flange is too large to fit inside a non-locking tube.