Clamps are an adjustable steel band that the user tightens with a screw. Most people generally know this kind of fitting as a Jubilee Clip which is often in the plumbers tool box. The premise is the same just on a bigger scale to suit ducting, not water pipes. The worm gear that adjusts the tightness allows a secure connection between ducting and fan or filter.

Many growers use ducting clamps in combination with Aluminium tape. This makes an even stronger join with advantages of both. The tape has a bigger surface area for joining and can go round and round as many times as you want. It can degrade after a while though so the Ducting Clamp will increase holding power of the join.