| Description | Part Number |
| MX521ade MFP | 36S0820 |
| ADF access door MX521) | 41X2228 |
| ADF assembly (MX521) | 41X2219 |
| ADF cable (MX521) | 41X2225 |
| ADF cable cover (MX321, MX421, MX521) | 41X2220 |
| ADF cushion (MX321, MX421) | 41X1323 |
| ADF cushion (MX521, MX522, MX622) | 41X1324 |
| ADF right hinge (MX521, MX522, MX622) | 41X1321 |
| ADF roller (MX321, MX421, MX521) | 41X2223 |
| ADF roller maintenance kit | MX521-ADFMK |
| ADF separator roller (MX421, MX521) | 41X2224 |
| ADF tray (MX321, MX421, MX521) | 41X1333 |
| Bezel (MX521) | 41X2500 |
| Bin extender | 40X9075 |
| Cartridge barrel sensor kit | 41X1988 |
| Cartridge gearbox | 41X1237 |
| Control panel (MX421, MX521, MX522) | 41X1359 |
| Control panel cover (MX421, MX521,MX522) | 41X1353 |
| Controller board (MX421, MX521) | 41X1361 |
| Cooling fan | 41X2259 |
| CS720, CS725, CX725 Card for IPDS | 41X1004 |
| CS720, CS725, CX725 Card for PRESCRIBE | 41X1006 |
| CS720, CS725, CX725 Forms and Bar Code Card | 41X1002 |
| Duplex asm | 41X1176 |
| Dust cover, 250-sheet tray | 40X8520 |
| Flat cable (MX521, MX522) | 41X2226 |
| Flatbed scanner (MX521) | 41X2227 |
| Front input guide | 41X1184 |
| Fuser actuator | 41X2255 |
| Fuser Maintenance Kit, 110V, MS521 MX52x | 41X1228 |
| Fuser Maintenance Kit, 220V, MS521 MX52x | 41X1229 |
| Fuser, 110V | 41X1178 |
| Fuser, 220V | 41X1179 |
| Interconnect cable | 41X1236 |
| Jam access cover | 41X1183 |
| Left cover | 41X1167 |
| Left hinge assembly | 40X8735 |
| Main drive gearbox | 41X1224 |
| MarkNet N8230 Fiber Ethernet 100BASEFX (LC), 1000BASE-SX (LC) (Fiber + side cover) (MX52x) | 41X1946 |
| Marknet N8372, Front WiFiFSM | 41X1872 |
| Memory 256MB User Flash Memory | 41X1010 |
| MPF gearbox (MS/MX52x, MS/MX62x) | 41X1182 |
| MPF pick roller and separator pad | 41X1197 |
| MPF solenoid | 41X1213 |
| MPF with front access cover (MX421, MX521) | 41X1366 |
| Nameplate (MX421, MX521, MX522) | 41X2273 |
| Optional 250-sheet tray | 41X1217 |
| Optional 550-sheet tray | 41X1216 |
| Parallel 1284-B Interface Card (MS610de, MX5/61x) | 40X8524 |
| Parallel cable, packaged (3 m) | 40X1367 |
| Pick roller | 41X1239 |
| Pick roller assembly | 41X1223 |
| Pick roller clutch | 41X2391 |
| Pick tire | 41X0918 |
| Power supply, 100V/110V | 41X1201 |
| Power supply, 220V | 41X1202 |
| Printhead | 41X1185 |
| Rear access door | 41X2263 |
| Rear door and cover | 41X1169 |
| Redrive assembly | 41X1349 |
| Redrive gear plate | 41X2268 |
| Restraint pad | 40X9110 |
| Reverse solenoid | 41X1214 |
| Right access cover | 41X1233 |
| Right cover (MX521, MX522) | 41X2272 |
| RS-232C Serial Interface Card (MS610de, MX5/61x) | 40X8523 |
| Sensor (bin full) | 41X2260 |
| Sensor (duplex and input) | 41X1206 |
| Sensor (front door) | 41X1209 |
| Sensor (MPF paper present) | 41X1210 |
| Sensor (narrow media) | 41X1241 |
| Sensor (trailing edge) | 41X1240 |
| Sensor (tray present) | 41X1238 |
| Separator roller asmy | 41X1212 |
| Smart card | 41X2055 |
| Speaker | 41X2229 |
| Standard 250-sheet tray insert (MS/MX52x) | 41X1220 |
| Toner cartridge smart chip contact | 41X1162 |
| Toner density sensor | 40X8046 |
| Top access cover | 41X1355 |
| Top cover (MX521, MX522) | 41X1342 |
| Transfer roll | 40X8393 |
| Tray 250-sheet tray insert (optional tray) | 41X1221 |
| Tray 550-sheet tray insert (optional tray) | 41X1222 |
| USB cable, packaged (2 m) | 40X1368 |
| Wireless module | 41X1873 |
| Wireless module cable | 41X2270 |
