Dusol Technologies Offer two dust collector, either top entry or hopper entry, depending on your particular needs. Top entry is the most effective design for fine dust. Since the air flow is downward, it aids the migration of fine particulate towards the hopper. Hopper entry is the proven choice for coarse, heavy dust and high dust loads, which require air -to-cloth ratios of 6:1 or less. Heavy particulate naturally move downward to the hopper. Our dust collectors are designed bag removal and a construction consisting of a top plenum, housing and hopper section. No matter what the design, these marks of superior craftsmanship remain constant.