I always recommend Suaoki, good value, good specs:

Suaoki T10 12000mAh (400A peak) Portable Car Jump Starter with Dual USB Charging Port https://www.amazon.com/dp/B019VU5ZRC/ref=cm_sw_r_cp_apa_AUx-xbGHZGKAW

They also have a 20000mAh (800A peak) for $89.99 these are the stats you should be comparing between models.