Hi Jeff, this is a conventional generator using a brushless alternator that produces a power output with harmonic distortion of +/- 5%.
A conventional generator is designed to run appliances with resistive and heavy loads, e.g. power tools, farming equipment, domestic applainces without microprocessors. Conventional generators can handle 'overloading' for short periods, where an appliance will surge (usually when starting up) briefly. However, conventional generators are not intended to run sensitive electronic equipment (e.g. TV's, laptops, mobile phones etc.). Conventional generators are built tough and are popular for trade, construction, farming, industrial use, plus certain domestic requirements.
The type of generator that produces pure sine wave output is an inverter generator. An inverter generator can run sensitive electronic equipment. Note that Inverter generators cannot handle large 'overloading' that conventional generators can. Too much overload on an inverter generator will cause the generator 'trip the breaker' and stop producing power. These inverter generators are quiet, fuel efficient and are designed for recreational use, small home backup, DIY tasks, small mobile business and small events.
Finally, its worth mentioning AVR Generators.  This type of generator has an Automatic Voltage Regulator (AVR) fitted, so they reduce large voltage fluctuations that can potentially damage appliances. These types of generators are commonly used for Domestic backup applications and small business backup requirements.