Tripods are usually composed of two parts: the legs and a detachable head. The legs should be of a closed, tubular cross section made with a strong, lightweight material (like aluminum) with relatively thick walls. Wooden tripods make excellent stable platforms, especially for larger, heavier telescopes, where portability is not a major consideration. Usually the legs have two or three telescoping sections for height adjustments and also to provide a compact, portable size when fully retracted. The sections are adjusted by means of a leg brace, the more common types being either a flip-lock or clamp lever or the threaded twist lock. Threaded twist locks offer good strength and rigidity, but take longer set-up and breakdown time. They are also subject to overtightening and can pick up sand and grit. Flip-lock or clamp levers are generally the most satisfactory overall because of quick set-up, trouble-free operation (easy to use with gloves), and long term durability. Some models offer friction or spring-loaded variable leg stops allowing wide spread leg positions and more flexibility in positioning the tripod. Leg braces can provide some extra rigidity without adding much weight. The tripod center post can be adjusted by simply sliding to position (lift type) or they can be gear-driven. The decision here is primarily a personal preference, with the gear-driven offering easy height adjustments and the sliding center posts are lighter and faster to use.
Thanks to our friends at Eagle Optics for providing this information!