Polaris IPL500-4C Polaris Vision Tap (Clear) 500 Mcm – 4 Awg Polaris Insulated Multi-Tap Conn 4 Port (Single Sided Entry)
https://nsiindustries.com/product/4-port-clear-multi-tap-pre-insulated-connector-500-mcm-4-awg/
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.