WW1 and WW4 effluent filters from Clarus Environmental have integral bypass protection screens to keep solids in the tank and out of the drainfield during servicing. The pleated design provides 132 linear feet of 1/16-inch filtration for the WW1 and 528 linear feet of 1/16-inch filtration for the WW4. The WW1 is designed for residential applications with flows up to 1,500 gpd. The WW4 is designed for both residential and commercial applications with flows up to 4,000 gpd. Both may be installed in parallel with additional units for greater flows. 800/928-7867; www.clarusenvironmental.com.