I personally have never used them, so I can't speak of the quality, but I've read on other forums of people using them with
the Traxxas brand, so they do fit.
Personally, even though I've ordered my batteries from Hobby city, I use Traxxas brand connectors.
BTW
When you order from Hobbycity, do yourself a favor and pay the little extra for the EMS shipping.
I ordered my Batteries on a Sunday night and they arrived on Thursday.