Adjustable guide vane for a turbine of an exhaust gas turbocharger and the turbine of an exhaust gas turbocharger

The invention relates to an adjustable diffuser for a turbine of an exhaust turbocharger, having a first insert portion (13) and oppositely arranged an the first insert portion (13) second insert (15), between a first wall (19) of the first insert portion (13) and a relative to this first wall (19) disposed second wall (20) of the second insert portion (15) comprises a supply duct (9) is formed, and in which the inflow channel (9) has a plurality of vanes (14) for deriving from the turbine through-flowing exhaust gas is positioned, and with a spacer element (16) which (a) is positioned between the first wall (19) and the second wall (20) for securing a distance. According to the invention at least one vane (14 ') of the plurality of vanes (14) is formed, the spacer element (16) receivable.