Polaris SC-300B CMP Splice Copper Short 300 MCM-Bell
https://nsiindustries.com/product/polaris-sc-300b-cmp-splice-copper-short-300-mcm-bell/
The POLARIS compression design creates a permanent, vibration-resistant connection that you can rely on with low contact resistance. Suitable for a wide range of applications, including power distribution, grounding and data transmission.