strained by an axial force said variation of length allows the coupling of the same covering element with connectors presenting lengths differing from one another application_number US 68157196 A description as can be observed in fig1 the covering element according to the invention indicated as a whole with 1 is applied to a connector 2 which presents two circular annular holes 21 and 22 which match the positive pole 31 and the negative pole 32 respectively of two adjacent elements of an electric accumulator indicated as a whole with 3 which in this way are connected in series obviously the connector 2 can also connect in series elements belonging to accumulators differing from one another said connector 2 once it has been coupled with the poles 31 and 32 is welded to them and then covered as can be observed in fig2 by applying to it the covering element 1 as can be observed in fig3 the covering element 1 comprises a body 10 which presents a first extremity 11 and a second extremity 12 placed opposite to each other which as can be observed in fig5 have profiles 14 and 15 respectively presenting the shape essentially of an arch of a circle which allow them to match the corresponding profile of the extremities 24 and 25 of said connector 2 it can also be observed that said covering element 1 is essentially hollow and lodges.