Hey super. Ester length is the difference, half-life... essentially the time it takes to kick in and time it takes for it to leave.... Essentially...
However, it does mean that mg for mg tren acetate has more trenbelone than tren enanthate.
Tren enanthate 100mg= 67mg trenbelone, 33mg ester
Tren acetate 100mg= roughly 88mg trenbelone, roughly 12mg ester.
I say roughly because I am going from memory on the acetate ester. I can't remember exactly, it was somewhere in the neighborhood of 12-16% ester.