Battery for Welch-Allyn 300 300 Vital Signs Monitor 420 420 Vital Signs Monitor Compatible with the following devices 300, 300 Vital Signs Monitor, 420, 420 Vital Signs Monitor, 4200-84, 42MOB Spot Vital Signs Monitor, 42NOB, 450EO, 450TO, 45MEO, 45MTO, 45NEO, 45NTO, 501-0015-01, 5300, 5300-101, 53NOP, 53NTB, 53NTL, 53NTO, 53NTO Vital Signs Monitor, 53OTO, 53OTO Vital Signs Monitor, 63NTB, Spot Check 420, Spot Check 4200B, Spot Check 420TB, Spot Check 42M0B, Spot Check 42MTB, Spot Check 42N0B, Spot Check 42NTB, SPOT VITAL SIGNS MONITOR, VSM 300, VSM 53000, VSM 530T0, VSM 530TP, VSM 5350P, VSM 53N00, VSM 53NOP, VSM 53NTO, VSM 53NTP, VSM 53OTO, VSM 53S00, VSM 53STP, Schiller America 300 Vital Signs Monitor, 420 Vital Signs Monitor, 53NTO Vital Signs Monitor, 53OTO Vital Signs Monitor, Grason Stadler 300 Vital Signs Monitor, 420 Vital Signs Monitor, 53NTO Vital Signs Monitor, 53OTO Vital Signs Monitor Compatible with Battery Part Numbers 4200-84, 4500-84, 501-0015-01, 5300-101, 7170-2, AS11277, B11277, B11400, B11453, MED0023, OM11277, Schiller America OM11277, Grason Stadler OM11277