Spool, 2-1/2", for 1-1/4" Axle and models with 9" or 11" Spacing, Fits JD 310, 315, 330, 331, 335, 340, 350, 355, 360, 375, 635, 640, 650, 670 discs. 637 disc with C spring bearing hanger. 510 and 512 disc rippers. 1710, 1710A mulch tiller. Replaces OEM# N240970, B34210