Will not fit models KX71, KX91-2/2S or U35-4. Replaces Kubota OEM Number(s) RB511-21702, RC411-21306. Side cover: QT 450-10, strength as follows: tensile strength ob (MPa): 2450 yield strength 00.2 (MPa): 2310 hardness: 160 ~ 210 hb.