Whats a sine wave?
Pure sine waves have much more “flow” to them. You could say their power has been “smoothed out” much more effectively. This is the same sine wave form delivered in conventional electricity, and you will need a (more expensive) pure sine wave inverter, if you hope to effectively power large appliances or power tools. If you do not require such a strong and consistent source of energy, then a modified or square sine wave inverter will do. The form of the wave is “choppier,” and the power provided might also be choppy. The modified or square sine wave inverter is also called a multi-step or stepped inverter.