We stock acoustic and regular ducting for indoor ventilation fans. Ducting for Hydroponics should be insulated with dacron or insulation wool - see the different types below. Silver aluminium ducting is great for rust prevention, but it is more flimsy. PVC coated ducting is great for stopping pin holes of light escaping from inside. Our fan silencers are value for money, and can be bent at right angles to exit a tent at the roof.