Any cross-reference recommended is only a suggestion, please review the manufacturer documentation to verify that any replacement parts are suitable for your application.
If you’re looking to replace the MX60 from OutBack Power Systems, as it has been discontinued, a good option may be the 2303-TP-SC48-60P-MPPT-ND from Tycon Systems Inc.
It isn’t a direct match to the original, but comparing the datasheet specifications (linked in the part numbers above), it is comparable and makes for a good alternative option.