The Dustick Duster is manufacturered by a US company called Advantage Products.
Dust will fall to the bottom of the cannister on the Dustick Duster (with 21-foot reach). A handle at one end of the pole is used to pump air all the way through the extension to the dusting canister and tip on the other end, causing dust to be expelled. We do recommend filling only halfway.
To prevent caking or clumping of dusts in the Dustick Duster you can add a small pebble or marble. Also be sure to shake occasionally and not leave dust in the cannister when not in use.
We would recommend that you do not fill it any more than half full. Unfortunately, putting a stone and/or penny in the bulb will help keep the dust from clumping too fast but you will still need to shake the duster occasionally.