MF-RX300/72-0 is a radial-leaded PTC resettable fuse designed for overcurrent protection in low-voltage power supply applications up to 72 V. The device features a hold current (Ihold) of 3.0 A and a trip current (Itrip) of 6.0 A, with an initial resistance of 0.03 O at 23°C and a maximum resistance of 0.08 O after 1 hour at rated current. It exhibits a maximum time to trip of 18.75 seconds and a tripped power dissipation of 3.2 W at 23°C. The component is constructed with flame-retardant epoxy polymer insulation meeting UL 94 V-0 requirements, is RoHS compliant and halogen-free, and operates reliably across a temperature range of -40°C to +85°C. Typical applications include security and fire alarm systems, loudspeakers, and power transformers where automatic resettable protection is required.