A magnetocaloric regenerator unit comprising (A) at least one magnetocaloric material unit having a higher temperature hot side and a lower temperature cold side during operation, wherein the magnetocaloric material unit contains at least one magnetocaloric material, (B) at least one magnetic unit for producing a magnetic field over the magnetocaloric material contained in the magnetocaloric material unit, (C) at least one magnetic shielding comprising at least one window wherein the at least one magnetic shielding is mounted flexible to allow movement of the magnetic shielding between at least one first position and at least one second position thereby insulating the magnetocaloric material contained in the magnetocaloric material unit from the magnetic field when the magnetic shielding is in a first position and allowing the magnetic field to act on the magnetocaloric material through the at least one window when the magnetic shielding is in a second position.