AYP4
Burndy AYP4 HYPLUG Alunimum Compression Adapters for #4 wire Lot of 5 Adapters
A nice feature is the Blaster quick-release mechanism for easy adjustments.
Burndy Ayp4 Compression Adapter, 4 Awg Max, Standard Barrel, Aluminum, Tan
You will find that the thermostat assembly stays cool to the touch during normal operation.