You just need one. If your sub amp only has one power supply then a 0 gauge to two 4 gauge will be fine. But if your sub amp has two power supplies then you'll need a 0 gauge to three 4 gauge out, though i'm not sure i've seen three 4 gauge out so four 4 gauge out would be your next choice. I have used stinger in the past. I'm not sure how much brands make a difference though.