Difference Between Estra and Norandrosta

A lot of products are out that supposedly contain this trenbolone precursor: Estra-4,9-diene-3,17-dione. Some products list this ingredient, and others list norandrosta-4,9-diene-3, 17-dione as the ingredient. From what I've read on the chemical supplier's  sites, these two are the same thing. 

Nevertheless, some supplement companies are claiming that their norandrostra product is a “cleaner” more refined version of the estra compound, while other companies that don’t carry these products claim their all gabage. What’s up with this crap?

Estra is a different way of writing “norandrosta.” They are the same product.

I can’t, however, tell you which product is “cleaner,” that’s a matter of lab testing and correct dosage.