This is what I use in my slash 4x4 vxl. I got this at my LHS for $65-$70. Not sure why this is pricier on Amazon. I have had it over a year. Comes with an adapter for Traxxas. I personally will not spend the extra $$$ on Traxxas batteries. I also don't like their chargers.

https://www.amazon.com/dp/B07F19FZM9/ref=cm_sw_r_cp_apa_fabc_PWQSAPMG7TKNF4Q69KAK