The REAL,original liquidex only comes in 20ml,4mg per ml vials.The others are all just knock-off,copycat versions of the original,which is alright.The original,REAL liquidex,as stated above is also much cheaper per mg than the other copycats.It's up to the individual if he wants to pay more or not.I prefer the REAL liquidex for cost reasons,not to mention it is the most incredible estrogen combatant I have ever used.I will never run another cycle,bulking or cutting,without it again.Just my.02.