Adjustable seatposts have quickly become the norm for all-mountain and freeride mountain bikes. When the first mechanically operated posts started to appear on long-travel bikes, they were heavy and finicky (the HiteRite aside, of course). However, advantages far outweighed disadvantages and their popularity quickly grew. adjustable seatposts have come a long way since then, and now products like the RockShox Reverb 125mm take advantage of extensive suspension technology to offer smooth, slop-free operation. By opting for a hydraulic actuation of a cable, the Reverb is the first post to eliminate any mechanical connection. Hydraulics may be cause for alarm, but if you're running disc brakes they're more than likely hydraulic -- and share the same, basic principles. Expect the Reverb to be as reliable and easy-to-service as any modern hydraulic disc brake. RockShox is so sure of hydraulics that they use it to operate their remote fork lock-outs too. In fact, both the Reverb and RockShox suspension lock-out systems use a bar-mounted XLoc remote.This system uses 2.5-weight fork oil, and comes with the necessary materials and instructions to shorten and bleed the line. It won't become contaminated with grit like cables, and it's also lighter than a comparable cable-actuated unit. Fluid in the line opens and closes the Reverb's main oil-flow valve, allowing the post to drop, and the aluminum knob at the lever controls how fast the post returns to its static position. The post has 125mm of travel, and its height is infinitely adjustable.RockShox has an advantage over other dropper post designs due to its extensive suspension technologies. For example, the seals used are optimized to prevent contamination from dirt and water, and, just like fork seals, they're free from friction out of the box. You'll also find an IFP, an internal floating piston, which is another shared technology from RockShox's forks and shocks.