The present invention describes a PEF (pulsed electric field) chamber, said PEF chamber 1 comprising a tube 2 with two open ends 3, 4 having attachment means 5, 6 enabling the PEF chamber 1 to be a plug-in device, wherein the tube 2 has a length L from one open end 3 to the other open end 4 and an inner width IW from one side of the tube to the other side of the tube in a cross section being perpendicular to the length L thereof, wherein the tube 2 has a geometrical narrowing of the inner width IW somewhere along the length L of the tube 2, and wherein the PEF chamber 1 comprises a grid 9 of an insulating material being arranged at the geometrical narrowing or electrode units 7, 8 being arranged opposite each other at the geometrical narrowing of the inner width IW along the length L of the tube 2. The plug-in feature of the present invention renders the PEF chamber to function as an l attachable and disposable PEF chamber.