This connector is a yellow, 750 kcmil with a length of 4.620 in (117,3 mm), a 1.031 in (26,2 mm) I.D. and a 1.594 in (40,5 mm) O.D.
The 3M™ Scotchlok™ Aluminum Connector 20019 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)