... WR-C simple-row ball and simple roller water pump apindle bearings(four-point angular contact) 1) Ball ... 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. 2 Material: Mainly the chrome Steel (GCr15) ... is 60-64HRC Application of water pump bearings: Widely used in auto, machine,etc Water pump bearing W series