What threads do the invert mini barrel use?

No the invert mini only works with cocker threads, but ansgear.com has barrel adapters you can buy. So if you buy the a5 style barrel you can buy a cocker to a5 adapter or if you want the 98 buy a 98 to cocker adapter or whichever barrel style you choose. The prices on all the adapters are the same and they are $13.99. This is the ansgear site link for adapters: http://www.ansgear.com/Barrel_Adapters_s/933.htm