A filtration system is disclosed. or more; and releasing agent particles, each of which includes a polyester block copolymer having a weight-average molecular weight of about 3,000 or less and containing a non-crystalline polyester block containing a cyclic structure in the main chain and a crystalline polyester block containing no cyclic structure in the main chain. Write enable signals, bit selection signals, and address signals for each of the code word bits are generated based on applying logical operands to a cascaded sequence of successively delayed signals synchronous with a local clock signal. The invention relies on a buoy or float for the lift of a ballast weighted piston and the ballast weighted piston, when descending, provides the means of creating pressure on the water entrapped in the cylinder, thus causing a pumping action. A ski boot incorporating such a sole is also provided.