Here is a J&J Revision 14 comparison with the J&J Revision 10. Both are shown with sunlight, chemical, and shock resistant, non-plumbing grade, FpVC barrel. Both of these were user converted from the standard 'plain air tire stem' filling, to onboard HPA air cylinder for multi-shot capabilities.
This is a J&J Revision 10. certified, stainless steel chamber, aluminum air blast blast valve in a fiber reinforced trigger.
The rest of options were added in his shop. He is the McGruder of the Wind Weapon fame.
An earlier J&J Multilauncher. This was the Revision 9.5 air launcher, with interchangeable barrels, and they added an home made line spool for Nerf. Switching barrels lets him use Nerf rockets to pull line where a shot bag may travel too far, or be dangerous to use.
No PVC pressure holding parts.
A collections of buttons used by DIY'ers. The top three are quite common, and are not designed to be a trigger. The bottom three are made for us, and not found anywhere else. Button 1 & 3 on the second row can be fitted with a safety cap.