I have been very pleased with this bottle jack.  I use it to operate a 20 ton hydraulic press for my jewelry business with an air compressor.  It works well.  I did find the black piece on the top difficult to work with the press and I could not get it off.  Eventually I used it enough that I was able to get it off and from then on, it worked exactly as I wanted it to.  Great price too.  I  compared the price to other sources and this was the best price.