"Finajet" was a veterinarian steroid that was discontinued in 1986. It was made by Hoechst-Roussell, and it came in 50ml bottles, with each ml having a concentration of 30mg. There were smaller bottles for smaller animals. I believe it was sold in both England and France. Finiplix was approved in 1993 for cattle implants. Years later, like 2000's, a lot of sources sold Tren Ace under various names, one being the one you mentioned above, FIna-ject. Many also spelled Finajet wrong and spelled it with having the "c" in the name.
I think after the first couple of years, most were buying the pellets as component-th rather than the name brand of Finiplix, which costed a lot more.