An apparatus is provided for protectively hold an elongated object during bending and stretching of the elongated object. The apparatus includes a shell, sleds and roller sets. The shell includes a wall, support portions longitudinally extending on an internal face of the wall, and grooves separated from one another by the support portions. Each of the sleds is inserted in a corresponding one of the grooves. Each of the roller sets includes rollers attached to a corresponding one of the sleds. Each of the rollers includes a tread. The treads together provide an axial tunnel. A surface of the elongated object is in contact with the concave treads of the rollers when the elongated object is rolled in the axial tunnel during bending or stretching of the elongated object.