Product review (5 stars): Works good - use them to do a quick connect in winter to my basement
Bought a pair of these, cut the dryer vent line to the outdoors, and added a line into the basement.  The new dryer vent line in the basement goes to an overhead basement vent with a thick filter on it to try and keep the lint out of the basement but allow the dry moist air to be vented back into my basement shop during the cold winter months.  When spring gets here, I do a 10 second quick disconnect and re-hook it up to the outdoor vent.  These are 4" vents, not 6" as it says in the item title.  The two plastic halves mate using three small tabs that stick out on one of them to fit into three holes in the other, you then twist slightly to connect them.  The connection is a flat mating (they do not fit inside each other).  The vent hose connection is a male on the other side of both, you fit the dryer vent hose over them and put a 4" hose clamp around the outside.