of differing size further this clearance allows the wrench 10 to be manipulated to best advantage about the fulcrum provided by the key 30 or a thumbturn for the wrench of fig3 to engage a localized portion of the circular outer edge surface of the lock cylinder with an opposing portion of the inner surface 32 while simultaneously engaging a portion of the inner surface of the slot 26 with an opposing surface of the key 30 thereby to provide bearing engagement between the wrench 10 and both the key 30 and the cylinder of the lock 12 accordingly the mechanical advantage necessary to rotate the lock 12 on rotation of the wrench 10 is provided while the extent of the fitting of the inner surface 32 against the outer edge surface of the cylinder of the mortice lock 12 may vary depending upon the relative diameters of the annular body member 14 and of the lock 12 a bearing engagement is thus provided therebetween and need only be an essentially tangential contact this contact between the inner surface 32 of the annular body member 14 and the lock cylinder can be varied by the user of the wrench 10 and can be located.