Thanks everyone for answering! :3
Urfontunately the boosters don't work in the Mystery Shop.
I want the longtail and it can only be obtained in the Mystery box...
A few years ago I bought 20 mystery boxes + two tiered spender and I didn't get it... (but i want to try again)
I guess it's because I always had bad luck buying things. xD
First of all I want to say I am new in the forum and I don't know if I am in the right place.
I've been looking for information about this but I haven't found anything..
My questions are:
1) How much probability is there of getting a permanent item from the Mystery box? or is it just luck?
2) Which are "Pen Stats" have the same probability?
3) Is the difference a lot when buying the offer x2? is better?
4) How many Mystery box you usually buy to get something permanent?
And sorry for my bad English I hope everything is undertood well~