Rollers are used to break up clumps of soil, especially after ploughing, but a Cambridge roller has ribs round the outside to groove the surface as it does so, and help prevent the earth being scoured by the rain. The roller has a stabiliser that can be put down to prevent it falling over when taken off the tractor. The rollers are folded up when the job it done, so it can be driven safely along the roads. Tractor not included.