IDEAL Main 500 - 2/0 AWG, Tap 4/0 - 4 AWG B-Tap Connector BTC500-4 - The Home Depot
4 Gauge Wire Ferrules Kit for Car Audio Awg Insulated Ferrule Connectors (En25-16) Cable Terminal Crimp Red Black Blue Yellow Green Furrels 100Pcs lkelyonewy: Amazon.com: Industrial & Scientific
Polaris 3/0-4 AWG and 2/0-2 AWG Bagged Insulated Connector, Grey IPLG3/0-3B - The Home Depot