Ferrule crimps

Exactly as JP says.

Just as with all connecting products, just make sure the ferrules used are to an appropriate standard, such as the German standards DIN 4662-1 or DIN 4662-4, French standard NF C 63-023, or UL standard UL486-F, and are the right cross-sectional area or configuration for the conductors being terminated. There are some available out there (eg from some on-line marketplaces) that don't appear to have a declaration to any particular standard.

Ferrules are generally unsuitable for Class I (single solid) conductors. They can generally be used for Class 2, Class 5 and Class 6 conductors in screw and cage type terminals unless stated otherwise by the terminal manufacturer. Some screwless terminals might also permit ferrules for Class 5 and Class 6 conductors under conditions stated by the terminal manufacturer.

Exactly as JP says.

Just as with all connecting products, just make sure the ferrules used are to an appropriate standard, such as the German standards DIN 4662-1 or DIN 4662-4, French standard NF C 63-023, or UL standard UL486-F, and are the right cross-sectional area or configuration for the conductors being terminated. There are some available out there (eg from some on-line marketplaces) that don't appear to have a declaration to any particular standard.

Ferrules are generally unsuitable for Class I (single solid) conductors. They can generally be used for Class 2, Class 5 and Class 6 conductors in screw and cage type terminals unless stated otherwise by the terminal manufacturer. Some screwless terminals might also permit ferrules for Class 5 and Class 6 conductors under conditions stated by the terminal manufacturer.