5-Port Black Heavy-Duty Pre-Insulated Connector, 750 MCM – 1/0 AWG
https://nsiindustries.com/product/5-port-black-heavy-duty-pre-insulated-connector-750-mcm-1-0-awg/
Polaris Black Heavy-Duty Multi-Tap Connectors form secure connections between multiple conductors with a rounded design and UV-resistant insulation coating. Installs with a hex key and torque wrench, with no need for cover and taping.