What the 171 V standoff and 353 V clamp mean on the board
It sits across a 171 V nominal rail and stays out of the circuit until a transient drives the line above its 190 V minimum breakdown voltage. At that point it avalanches and clamps the surge to 353 V maximum at the rated 11.3 A peak pulse current (8/20 µs waveform).
Peak pulse power and the waveform that defines it
The 11.3 A peak pulse current figure carries an 8/20 µs waveform annotation, which is the typical IEC 61000-4-5 combination-wave generator output. That means the part is characterised for both the longer telecom surge and the faster EMC surge, so you can size it against either test level without re-rating.
Package and temperature range for the environment
The operating junction temperature range is -55°C to 150°C, which covers industrial, telecom outdoor cabinets, and under-hood automotive modules (the part is not AEC-Q101 listed in this evidence, but the temperature grade alone supports non-automotive harsh environments).