PVC-coated flexible ducting in 4.5 m lengths, stocked in 250 mm and 300 mm. The coating makes it completely light-proof, and the low-profile corrugation gives it a larger true inner diameter than standard flexible duct of the same nominal size — which means less turbulence, more airflow and quieter air passage on the big-bore runs where it matters most. Note that this is not an AC Infinity product.
Why the corrugation profile matters at 250 and 300 mm
Every ridge on the inside of a flexible duct trips the airflow and turns part of it into turbulence, which shows up as both lost pressure and audible rushing noise. The finer the corrugation and the larger the true internal diameter, the less of that happens. On a 250 or 300 mm run moving serious volume, the difference between a coarse duct and a smooth-profile one is something you can hear from across the room.
Memory duct
The wire-and-PVC construction holds whatever shape you bend it into, so a run stays where you put it instead of springing back or sagging into the airflow path. That makes it straightforward to route around obstacles and keep bends wide.
Specifications
| Sizes stocked | 250 mm (10″) and 300 mm (12″) |
| Length | 4.5 m per piece |
| Construction | PVC-coated memory duct over wire helix |
| Light transmission | None — fully light-proof |
| Profile | Small corrugation, large true inner diameter |
| Brand | Phresh — not an AC Infinity product |
FAQ
Which size do I need?
Match the duct to your fan and filter ports. A 250 mm fan takes 250 mm duct; stepping down to a smaller duct throttles the fan and adds noise. If you need to change size mid-run, use a reducer rather than forcing a mismatch.
Do clamps come with it?
No — order clamps separately. Stainless steel duct clamps are stocked up to 250 mm in 2-packs.
Is it AC Infinity?
No. This is Phresh ducting, stocked because AC Infinity’s four-layer range covers 100–200 mm and this fills the 250 and 300 mm end. For 100, 150 and 200 mm the AC Infinity four-layer ducting is the one to choose.
Can I cut it to length?
Yes. Cut the wire helix with tin snips and trim the sleeve back, then clamp the cut end onto the port.