I find a couple of bad review of this product but can only assume the reviewer be compare it to a full dust extraction system because for a simple fabric bag this work perfectly . Catches 80-90 % of the sawdust -lrb- which from a Bosch saw be considerable -rrb- , just a small amount below the saw . without it you 'll be sweep for age - or worse you wife will leave you ! Money well spend , simple , effective , not a vacuum system - but a fraction of the cost .