The internal diameter of the hose required is 32 mm (1 1/4"). An approx. 1 m section of hosing is supplied along with the accessory, that reaches over to the side of the machine. You then mate your vacuum cleaner nozzle with this, or replace the supplied hose with your own custom length hosing for your particular needs. Check out Amazon for 'Pond Hose' and you should be able to buy the hose in metre length multiples. The pond hose is good because it has a smooth internal surface that doesn't catch the dust and debris and therefore doesn't clog up.