@Normkel Thank you, again!! I know Remington changed to teflon O-rings in the 1100 shotgun because of the neoprene (or maybe Viton) failures. Interesting video; the Nuoge doesn't appear to be near as complicated, probably because it is a less expensive unit.
The piston sealing rings are also a different shape than are O rings. IME, O rings are not suitable for high rates of reciprocation, especially without very significant lubrication. I understand that O rings, in reciprocating applications, operate on an oil/lubricant film.
O rings are common in such reciprocating applications as automatic transmission spool valves, hydraulic pistons, ABS brake module pistons, etc. The cannot handle applications such as compressor piston seals, IMO.
I agree with the assessment, "the Nuoge doesn't appear to be near as complicated, probably because it is a less expensive unit.".
The same is the case for Yong Heng & clone compressors as compared to New Warrior Mini Luxury Compressor which seems virtually identical to Benjamin Recharge 4500 PSI Compressor. They have parts that are identical but additional components and refinements.
I am pleased to share that I understand about these compressors, as a service to others, and in the hope that someone may correct errors take some of the information to a higher level.
I like the "industrial" aspect of the Nuoge and clones as the ability to service is better than most other types. It is slower than the CS3, or Yong Hengs, although I stepped away from the YH types for various reasons. I owned a New Warrior, which is the physical size and weight of a GX CS4. I don't contemplate owning another, or a CS4 because of the size and weight, given that mine go to the range to work for ~one hour pumping each week.
New Warrior, GX CS3, Nuoge.