SMD0603P050TF

Ihold = Hold current: maximum current device will pass without tripping in 23ºC still air. 
Itrip = Trip current: minimum current at which the device will trip in 23 ºC still air. 
Vmax = Maximum voltage device can withstand without damage at rated current (I max) 
Imax = Maximum fault current device can withstand without damage at rated voltage (Vmax) 
Pd typ = Typical power dissipated from device when in the tripped state at 23 ºC still air. 
Rmin = Minimum resistance of device in initial (un-soldered) state. 
R1max = Maximum resistance of device at 23 ºC measured one hour after tripping or reflow soldering of 260 ºC for 20 sec.