at its outer end spring clip 18 functions as a retaining ring and is clipped into an annular groove 19 of the lateral base 15 and the inner diameter of the clip includes room for the key shank 10 39 which is to be inserted through the ring the radially protruding tumblers 10 act together with fixed locking shoulders 20 the latter are formed on a separate annular body r placed into an axial chamber 21 of the polygonal head 5 and fixed thereto the components used are turned components which are completely identical in shape which can be manufactured economically on automatic machines in conformity with the number of tumblers 10 five of such annular bodies r are inserted into the axial chamber 21 abutting each other the axial thickness corresponds to the axial spacing dimension from lock shoulder 20 to locking shoulder 20 the inside diameter of the annular bodies r corresponds to the inside diameter of the location cavity 12 for the lock housing 11 the annular bodies r thus occupy the diameter of this location cavity 12 up to the free end face 5 39 of the polygonal head only interrupted by a recess 22 which provides the locking shoulder 20 the recess 22 takes up roughly half of the length of the annular body r and is located so that it runs departing from the cylinder lock location cavity area in the corresponding annular end face 23 pointing in the insertion direction arrow y of the cylinder lock 9 in this way an approximately.