Yong Heng (where to purchase)

You really don't know if you are getting the latest generation of internal parts. I have questioned these sellers and came up with no definitive answer about the upgraded parts. I know mine has the older stuff because I bought it some time back. What I did was buy a new piston that is thicker than the original. It is one of the main items to fail on the older compressors.
 
I'm not so sure that having the newest parts really matters. I have a two year old and a new one the old one has been overheated badly three times the new one only once. The new one died seems someone forgot to locktight the second stage piston. It banged into the head and destroyed itself. The old one keeps on truckin even after being mistreated. So me thinks what really matters is how it was put together and how you take care of it.