'Booster' bar is a pipe fitted iniside a washer barrel with spray holes and attached to a high pressure recirculation pump.

When crop conditions are difficult and soil is stubborn to remove from tubers then the 'booster' bar makes a big difference.

A 'booster' bar also has a filter elevator fitted tto the side of the water tank to remove floating debrise.  This prevents the recirculation pump from blocking (see 'filter elavator' section).