Whats the difference between animal stak and animal stak 2?

Stak is a natural test booster which I usually will throw into my stack when I hit a strenght platue to give my natural test a nice boost and gain some solid strenght as well as size.

M-stak I use when Im bulking to help add that nice lean mass we all crave! M-stak is a nutrient partitioner which will help in adding solid lean mass, when diet and training are in check.