Swoop...it is one of the secondary cylinders, I do not have the mast number with me, It is at work, but it does bolt infrom the top, I'm just trying to figure out how to get the cylinder out at the bottom, as it looks like the mast has to be all the way in the upward position to be able to remove it from the bottom area of the mast. I tried to unbolt the top bolt and block the slides and lower it the other day to see if I could get the piston to come out of the top part of the mast, but it would not budge, thats why I was wondering if it is "screwed" into the top cap, or if it just sits in there with just the one single bolt from the top? Thanks Swoop!