The most recent development in the field of pumped concrete is the use of a new squeeze principle to provide the necessary pressure to transport the plastic mix. This method has a major advantage from the maintenance viewpoint in that there are no moving parts actually in contact with the concrete during the pumping. Ready mixed concrete is discharged into a collecting hopper, inside which there are 3 rotating blades to ensure that the concrete accumulates around the mouth of the 3 inch diameter pumping tube. A pair of rubber rollers, operating on a planetary-drive principle are then pressed over the tube to create a squeezing action which forces out the concrete like toothpaste. This squeezing takes place within a large circular drum that is kept under a reasonably high vacuum; this means that, after the squeezing, air will be sucked back into the tuber in an attempt to fill this vacuum and in so doing forces the tube back to its normal shape. Small line pumping's biggest appeal lies in the smaller volume job because the hoses are flexible and comparatively lightweight. Since pressures are lower, there is no need for special bracing and the setting-up of a small line system rarely takes more than 30 minutes.