This Ring Set, E-Ring Etw-7 Sus (50 pcs) is suitable for Roland RA-640 printers. This is the original Roland part (number 31149705).
 
Printer compatibility
Roland SG-540
Roland SG-300
Roland AJ-1000
Roland AJ-1000i
Roland AJ-740
Roland AJ-740i
Roland CJ-400
Roland CJ-500
Roland CJ-540
Roland EGX-400
Roland EGX-600
Roland FJ-400
Roland FJ-42
Roland FJ-500
Roland FJ-52
Roland FJ-540
Roland FJ-600
Roland FLJ-300
Roland FP-740
Roland LEC-300
Roland LEC-300a
Roland LEC-330
Roland LEC-540
Roland LEJ-640
Roland PC-600
Roland RA-640
Roland RE-640
Roland RF-640
Roland RF-640a
Roland RS-540
Roland RS-640
Roland SC-500
Roland SC-540
Roland SC-545ex
Roland SJ-1000
Roland SJ-1045ex
Roland SJ-500
Roland SJ-540
Roland SJ-600
Roland SJ-640
Roland SJ-645ex
Roland SJ-740
Roland SJ-745ex
Roland SP-300
Roland SP-300i
Roland SP-300v
Roland SP-540i
Roland SP-540v
Roland VP-300
Roland VP-300i
Roland VP-540
Roland VP-540i
Roland VS-300
Roland VS-300i
Roland VS-420
Roland VS-540
Roland VS-540i
Roland VS-640
Roland VS-640i
Roland XC-540
Roland XC-540mt
Roland XF-640
Roland XJ-540
Roland XJ-640
Roland XJ-740
Roland XR-640
Roland VG-640
Roland VG-540
Roland EJ-640
Roland XT-640