Pleat welded seam (the best sealing & strongest design) Passes ASTMF316 Test for 35 Microns Passes 24 hour chemical resistance test Woven media element is durable, able to withstand 600 degrees F* Full Flow bypass with progressive valving, no disassembly for cleaning Fits all Beta 4-stroke RR/RS/RR-S excluding 125 RR-S