2-Port Clear Multi-Tap Pre-Insulated Connector, 1/0-14 Gauge
https://nsiindustries.com/product/2-port-clear-multi-tap-pre-insulated-connector-1-0-14-gauge/
Polaris Vision Tap Multi-Tap Connectors form secure connections between multiple conductors with a transparent rounded design and chemical-resistant insulation coating. Installs with a hex key and torque wrench, with no need for cover and taping.