2-Port Black Multi-Tap Pre-Insulated Connector, 1/0 – 14 AWG
https://dev.nsiindustries.com/product/2-port-black-multi-tap-pre-insulated-connector-1-0-14-awg-2/
Polaris Black 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.