Our trunks are not made of cardboard, but of solid wood - just like real trees. This makes our scratching posts extraordinarily stable - and they stay like that. | The screws connecting the trunks have a diameter of 10 mm (0.39") The wood-embedded steel sockets for the connecting screws cannot be pulled out. It is extremely stable. | Our trunks have a diameter of 12 cm (4.72"). The sisal rope is wrapped very tightly around the wood and additionally held in place by (formaldehyde-free) wood glue. The rope ends are embedded in grooves and firmly stapled into place on both ends of the trunk. |