Greenteeth Lopro 900 Series (Green) The 900 LoPro Series green teeth are less concaved than the 900 Series red teeth, which work well in situations where there is some rock in the soil. The 900 Series green teeth still cut wood at a fast rate, but are less prone to chip when compared to the 900 Series red teeth. The green teeth are recommended in situations where there is more than 25% rock in the ground.