All ducted vacuum systems use the same 50mm (2 inch) pipe and fittings regardless of their make/models. Please note that ducted vacuum pipes are not the same as the water plumbing pipes; ducted vacuum pipes are 50mm O.D. (outside diameter) while plumbing pipes are 50mm I.D. (inside diameter). In certain situation, where you need to run your pipework under the ground/concrete, you can use plumbing pipes instead of ducted vacuum pipes, so that the pipes can withstand more pressure from its surrounding. Should you need to do this, you will need to revert it back to the 50mm pipe connection by inserting a short piece of ducted vacuum pipe before or at the wall ends.