The WW4 effluent filter from Clarus Environmental has integral bypass protection screens to keep solids in the tank and out of the drainfield while servicing. The pleated design provides 528 linear feet of 1/16-inch filtration. It is designed for both residential and commercial applications with flows up to 4,000 gpd. It can be installed in parallel with additional units for greater flows. 800/928-7867; www.clarusenvironmental.com.