supply 150 kinds of water pump bearings. 1) Material: GCr15 grade steel with oxygen content less than 20ppm 2) Hardness for rings and rollers: 59 - 63HRC 3) competitive price and good service. Water pump bearings are primarily used in automotive water pumps, basically consisting of standard double row bearings. These bearings are available in two main types: 1) Ball-ball: With two rows of balls; WIB, BWF, WS, WK, 885000 series, etc. 2) Ball-roller: With one row of balls, one row of rollers; WIR, WN, WKH, 665000 series, etc.