Model SMBWSheet molded fiberglass tank, 2 in. threaded female connections with Noryl rotary backwash valve. FEATURES: Maximum Operating Pressure 50 psi Corrosion-resistant 20 in. diameter fiberglass filter tank for strength and durability Unique Spiro-Mite grid design provides high efficiency filtration and longer filter cycles Exclusive clamp ring design is proven to be safe, strong and reliable. It allows for quick and easy access to internal components 2 in. plumbing connections provide maximum flow 35 SQFT SMBW 4036 D.E. FILTER WITH BACKWASH VALVE 011554 $1,149.00 47 SQFT SMBW 4048 D.E. FILTER WITH BACKWASH VALVE 011555 $1,299.00 58 SQFT SMBW 4060 D.E. FILTER WITH BACKWASH VALVE 147411 $1,399.00