A main indication element of the device are LEDs, displaying a measuring voltage value, phase rotation and polarity (at DC voltage). UT15C has moreover in comparison to UT15B an LCD display, displaying a value of tested AC and DC voltage. In dark or constrained environment can be helpful also a possibility to illuminate a measuring tip by a built-in white LED torch, controlled by switch placed on a rear cover. Detailed information will provide you the UT15 instruction manual.
[Source] SOS Electronics