A handpiece assembly 100 for an apparatus used in non-invasive cosmetic treatment, in particular, in an apparatus for non-invasive fat reduction by means of cold-induced lipolysis of fat cell, known as cryolipolysis, is provided. Said handpiece assembly 100 comprises a handle 10, provided with a control terminal 14 equipped with a user interface, said handle 10 being connectable to the treatment unit of the apparatus for cosmetic treatment by a number of fluidic and/or communication lines a treatment head 50 configured as a cup-shaped body applicator 20 disposed between at least two cooling units 30, and an adapter 40 configured to connect the handle 10 and the treatment head 50, wherein the connection between the handle 10 and the treatment head 50 mediated by the adapter 40 is releasable.