E marks the enanthate ester in Pharmacom Labs' naming scheme and the 200 gives the strength: 200 mg/ml, ten millilitres per vial.
The long chain is what sets this apart from the acetate-coded product in the same range. Instead of a sharp rise and fall inside a few days, the enanthate form lets the hormone off gradually over a much longer stretch, which is why it is grouped with the slow injectables. Trenbolone converts to oestrogen at no point in that process. Pharmacom fills its whole line into uniform vials with the product code printed on the face of the label.
