The Rock Shock Reverb Hydraulic Fluid (120ml) is designed specifically for bleeding the Rockshoc Reverb dropper post and Xloc systems. The main symptom of a dropper post in need of a bleed is that the seat post will not return to full extension quickly. Get your Reverb working again with factory specified Rock Shox Reverb Hydraulic Fluid. This fluid can also be used to bleed the x-loc remote on your rockshox fork, monarch rear shock or Lefty!