Evo coil head on protank is leaking at the base

[unclestu]

I have some Protanks and I just ordered some replacement heads. I also ordered 2 5 packs of evo replacement heads that can be used on the protank as well. They do provide a tighter draw however I did notice some leaking at the bottom of the 510 connector. Is this common with this head as I really never experienced this with the protank heads? Thanks Stu