Single-row	Double-row		Four-row
	TDO type	TDI type	Mainly used on rolling mill roll necks
(Standard contact angle) 32900JR 30200JR 32000JR 32200JR 33000JR 33200JR 33100JR 30300JR   32300JR (Intermediate contact angle) 30200CR 32200CR 30300CR 32300CR (Steep contact angle) 30300DJ 30300DJR 31300JR	46200 46200A 46300 46300A (46T)	45200 45300 (45T)	37200 47200 47300 (47T)

Single-row bearings can accommodate radial load and axial load in one direction, and double-row bearings can accommodate radial load and axial load in both directions. This type of bearing is suitable for use under heavy load or impact load. Bearings are classified into standard, intermediate and steep types, in accordance with their contact angle. The larger the contact angle is, the greater the bearing resistance to axial load. Items sized in inches are still widely used.