These printers use the RC300BR cartridge:

Star-Micronics MP 300

Star-Micronics MP 312 F

Star-Micronics MP 317

Star-Micronics MP 321 S-24

Star-Micronics MP 322 S-24

Star-Micronics MP 323 S-24

Star-Micronics MP 342

Star-Micronics MP 347

Star-Micronics MP 352 S

Star-Micronics MP 382

Star-Micronics SP 300

Star-Micronics SP 310

Star-Micronics SP 311

Star-Micronics SP 312

Star-Micronics SP 316

Star-Micronics SP 320

Star-Micronics SP 321 SProCKET

Star-Micronics SP 322 SProCKET

Star-Micronics SP 323

Star-Micronics SP 341

Star-Micronics SP 342

Star-Micronics SP 347

Star-Micronics SP 348

Star-Micronics SP 349

Star-Micronics SP 389

Citizen MP 300

Citizen SP 300

Samsung ER 350

Samsung ER 550

Samsung ERP 200

Samsung SMP 200

Samsung SRP 100

Samsung SRP 200

Samsung SRP 250