Bell & Gossett P75423 Seal Kit (EPR/SiC/SiC) is a non-standard, optional selection that should only be used when fluid has higher than standard levels of pH (7.0 to 12.5) or higher than standard levels of dissolved solids (25,000 ppm), undissolved solids (40 ppm), or silica (20 ppm). Repairs Series e-80, Series e-1510, Series e-1531, and Series e-1532 with 1.25" shaft sleeve diameter at mechanical seal (small bore).