Test-Plex is the name Magnum Pharmaceuticals gives its testosterone mixture, and the 300 refers to the milligrams of hormone in each millilitre of oil. It is packed as a 10 ml vial, the format Magnum uses for most of its injectable range.
A blend means several esters of the same hormone share the bottle, so the substance enters the bloodstream in staggered fashion rather than all at once. Taken as a whole it behaves as a long-acting injectable, despite the short esters in the mix. Nothing here is swallowed - it is an oil for intramuscular use only.
