The Best Filter is a great addition to the Polylok PL-525 effluent filter family. The GF10 Filter is 10" x 18" and is available in three filtration designs: 1/8", 1/16" and 1/32". The exterior of the GF10 filter is a single-piece case. It has no joints and no glue holding it together which gives it incredible strength. It is made of impact-resistant PVC so it can withstand harsh treatment and it won't break!