This connector is a dark blue, 300 kcmil with a length of 3.120 in (79,2 mm), a 0.650 in (16,5 mm) I.D. and a 1.010 in (25.6 mm) O.D.
The 3M™ Scotchlok™ Aluminum Connector 20010 is for use with copper or aluminum conductors. These aluminum connectors feature color coded end caps for identification. Contact aid provided in connector barrel is compatible with poly/EPR insulations.
Scotchlok Aluminum Compression Connectors - Data Sheet (PDF 37.2 K)