Rectangular baler comprising a bale chamber adapted to contain one or more bales； a compacting plunger for advancing crop material in a direction towards a discharge opening of the bale chamber； wherein the rectangular baler further comprises at least one friction block mounted moveably in a wall of the bale chamber such that at least a part of each friction block is moveable out of the wall； and biasing means adapted for biasing said at least one friction block in a position wherein said at least one friction block protrudes out of the wall.
