Sta-Kon RC4F POLYCARBONATE FORK TERM, 4-6MM, YEL

The RC4F is sized for 4 to 6 mm2 conductor, which is the yellow color code band in metric insulated terminals. In AWG terms that range covers roughly 12 to 10 gauge wire. If you are terminating 1.5 to 2.5 mm2 you need the blue-range terminal instead, not this one.

It is a fork (spade) terminal, so the tongue is open at the end. You can slide it under a loosened terminal screw and pull it back out without backing the screw all the way out of the block. That is the reason to pick a fork over a ring on panel work where you are re-terminating often. If you need a connection that cannot vibrate off the stud, use a ring terminal instead.

Yellow is the metric color code for the 4 to 6 mm2 conductor range, so the insulation color tells an electrician at a glance that the terminal matches that wire size. It is not a cosmetic choice. Red covers the small end of the range and blue the middle, which is how techs sort a panel's worth of crimps without reading part numbers.

The crimp barrel is electrolytic copper, with polycarbonate insulation over it. Copper barrel means the crimp conducts at the same conductivity class as the copper conductor you are putting into it, and polycarbonate holds up better to heat and mechanical abuse than the soft vinyl sleeves on economy terminals.

Use an insulated-terminal crimp tool with a die sized for the 4 to 6 mm2 / yellow range. Crimping a yellow-range barrel in a smaller die under-forms the joint and a loose crimp is what fails later under load. The insulation is polycarbonate rather than nylon or vinyl, so set the tool and work the handle through its full stroke rather than trying to squeeze it in a general-purpose plier.

Order it as Sta-Kon RC4F. It is manufactured in Sweden. One model covers the whole 4 to 6 mm2 yellow range, so there is no finish or size option to specify on top of the part number.