LOCKING MECHANISM

Length is usually adjusted by an external lever, operating a clamping mechanism (the flicky kind); or by an internal expanding clamping system (the twisty version). The latter doesn't snag on rocks or undergrowth, but the poles will need drying after use to prevent corrosion cuased by internal moisture build-up. The lever mechanism is gaining popularity as it's quick and easy to use, and appears not to succumb to operating problems easily, but it can snag on undergrowth.