a length - adjustable tube for trekking sticks etc , comprising an outer tube and an inner tube insertable telescopically into the outer tube , and an expanding device with which the inner tube is clampable in the outer tube . the expanding device has an expanding element which can be pushed apart radially and is provided with a taper , and an inner element which is provided with an opposed taper and is accommodated in the expanding element . an adjustment screw held on the inner tube is operatively connected to an internally threaded bore in the inner element a clamping section is arranged on the expanding element , which , in a relaxed state , has a greater radius than the radius of the expanding element . the clamping section is elastically offsettable inwards counter to a restoring force .