MF-RX300/72-AP is a radial-leaded PTC resettable fuse designed for circuit protection in low-voltage power supplies 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 23°C. It provides automatic protection with a maximum time to trip of 24.0 seconds at 23°C and dissipates 3.2 W in the tripped state. The component is constructed with flame-retardant epoxy polymer insulation meeting UL 94 V-0 requirements, operates across a temperature range of -40°C to +85°C, and is RoHS compliant and halogen-free. Common applications include security and fire alarm systems, loudspeakers, and power transformers where reliable overcurrent protection is essential.