Abstract: A locking mechanism releasably holds an elongated first member sheathed within an elongated second member at selected positions of telescopic extension and retraction between first and second end limits of travel. The locking mechanism preferably includes an elongated lock member disposed within the second member. The locking mechanism has at least one radially inwardly extending obstruction or projection movable between a first position preventing relative movement between the first and second members, and a second position allowing relative movement between the first and second members. A first embodiment of the locking mechanism provides for longitudinally reciprocal actuation of the elongated lock member between locking and releasing positions. A second embodiment provides for angular actuation of the elongated lock member between locking and releasing positions.