Right now, there are 2 kinds of Harvestor. HotRod and the normal Harvestor.
The Hot Rod Harvestor was introduced to bring Farmers to play Mafia Wars. It allows you to plot 9 plots (3x3 plots) with one click. Farmers needed to gain a certain number of levels (depending on whether they joined Mafia Wars before the promotion) in order to buy it with FarmVille Coins.
The Harvester allows you to harvest only 4 plots (2x2 plots) with one click.
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