All those products that claim to be a safe legal substitute for R12 are bogus. They all contain mostly propane ( which by the way makes for an excellent refridgerent). However it has never been approved by the EPA for automotive use. It is acceptable to a very limited extent in some industrial applications.
These products are highly flamable , dangerous, and will cause major damage to your automotive AC system over a period of time.
Whenever anyone tries to sell me any of this garbage I refer them to the following site.