| Description | Part Number |
| Bezel (MS421) | 41X1156 |
| Cartridge barrel sensor kit | 41X1988 |
| Cartridge gearbox | 41X1237 |
| Control panel covers (MS321, MS421) | 41X2264 |
| Control panel display assembly (MS321, MS421) | 41X2047 |
| Controller board (MS321, MS421) | 41X1191 |
| Cooling fan | 41X2259 |
| Duplex assembly | 41X1176 |
| Dust cover, 250-sheet tray | 40X8520 |
| Flat cable, 2-line display (MS321,MS421) | 41X2266 |
| Front input guide | 41X1184 |
| Fuser actuator | 41X2255 |
| Fuser, 110V | 41X1178 |
| Fuser, 220V | 41X1179 |
| Interconnect cable | 41X1236 |
| Jam access cover | 41X1183 |
| Left cover | 41X1167 |
| Main drive gearbox | 41X1224 |
| Memory 256MB User Flash Memory | 41X1010 |
| MPF gearbox (MS/MX321, MS/MX421) | 41X2271 |
| MPF pick roller and separator pad | 41X1197 |
| MPF solenoid | 41X1213 |
| MPF with front access cover | 41X1218 |
| Nameplate | 41X1163 |
| Optional 250-sheet tray | 41X1217 |
| Optional 550-sheet tray | 41X1216 |
| Output extender | 41X2262 |
| 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 | 41X1203 |
| Redrive gear plate | 41X2268 |
| Reverse solenoid | 41X1214 |
| Right access cover | 41X1233 |
| Right cover | 41X1165 |
| Sensor (bin full) | 41X1211 |
| Sensor (duplex and input) | 41X1206 |
| Sensor (front door) | 41X1209 |
| Sensor (MPF paper present) | 41X1210 |
| Sensor (trailing edge) | 41X1240 |
| Sensor (tray present) | 41X1238 |
| Separator roller assembly | 41X1212 |
| Smart card | 41X2055 |
| Software CD | 3086579 |
| Standard 250-sheet tray insert (MS/MX321, MS/MX421) | 41X2125 |
| Toner cartridge smart chip contact | 41X1162 |
| Toner density sensor | 40X8046 |
| Top cover | 41X1171 |
| 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 |
