This is a 500 kcmil compact stranded connector with a 4.25 inch body and a 1.3 in (33 mm) O.D., that are for splicing applications on aluminum or copper cable products
The 3M™ Connectors CI Series are for splicing applications on aluminum or copper cable conductors. The aluminum connectors CI Series are specially designed for use with 3M™ QS-I, QS-II and QS-III Pre-molded Power Cable Splice Bodies. These connectors meet the requirements of ANSI C119.4.