... excellent surface 3.never rust Horizontal Stainless Steel Sand Filter Stainless steel filter is a new kind of pool dedicated high-speed ... computer grinding, polishing,(3) patent design, filter more thoroughly; (4) the filter has big filter area, a medium speed, high speed model ... any pollution; (8) durable, its use life for 50 years, is common glass fiber sand cylinder 10 times!Work flowFeatures1 ...