Pentek - BBF1-20MB - 20" x 4.5" Mixed Bed DI Resin FilterThe Pentek BBF1 20MB is a 20" x 4. 5" mixed bed deionization resin cartridge engineered to remove dissolved solids and reduce total organic carbon (TOC) for high purity water applications. With a 1,850 grain capacity and semiconductor grade, FDA compliant resin, this filter delivers low TDS and TOC output at 1. 25 GPM for pharmaceutical, laboratory, and industrial use. SPECIFICATIONS Performance & Capacity Grain Capacity 1,850 grains 120,000 total TDS