This is a 750 kcmil compact stranded connector with a 4.66 inch body and a 1.7 in (43 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 CI Series aluminum connectors 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.