The electric contacts comprise a first set (2) of stationary elements and a second set (3) of movable contacts alternating along the fastening between the closure edges. When not operating, the electric elements form a closed circuit. When operated, at least one movable contact of the second set is removed from at least one stationary contact of the first set and thereby breaks the circuit. The inside of the convex switch part (4) of the elastic tubing (1) has a number of T-sectioned dies (5) the ends (6) of which on their sides facing the switch part have the second set of movable contacts. The first set of stationary contacts on at least one stationary transverse bar (7) are positioned on gaps with which they overlap with the second set.
