Sta-Kon RC703 INS NYL RNG TERM 12-10 BLT 5/16 YEL

The RC703 is sized for 12-10 AWG conductors. That is the yellow color code on nylon insulated terminals, so if you are crimping 16-14 AWG (blue) or 22-16 AWG (red), this is the wrong barrel and the crimp won't hold. Match the terminal to the actual conductor, not to the lug size.

600 V is the rating on the RC703, which covers standard commercial and industrial branch circuits, control panels, and motor terminations. It also carries UL file E9809, so it can be used where an inspector wants a listed termination.

Two separate choices here. Nylon insulation takes more abuse than vinyl, it resists cracking when the barrel is crimped and holds up better to heat and solvents, which is why panel builders spec it on 600 V work. The ring tongue versus a spade: a ring will not come off the stud if the nut backs off slightly, so it is what you want on vibrating equipment, motor leads, grounding studs, and anything an inspector looks at. A spade or flanged fork is only for places you need to pull the wire off without fully removing the nut.

The barrel is copper. That makes it a copper-only termination, so use it on copper conductors. Aluminum conductors need a terminal rated AL/CU with the appropriate compound, and putting bare copper against aluminum invites galvanic corrosion at the joint.

Order Sta-Kon RC703. The yellow insulation identifies the 12-10 AWG barrel and the 5/16 inch ring tongue is what distinguishes it from the smaller stud sizes in the same series. It is made in the United States.

Insulated nylon ring terminals like the RC703 are crimped with an insulated-terminal crimper matched to the 12-10 AWG (yellow) nest. A yellow-coded die or the 12-10 position on a controlled-cycle tool gives the right compression; pliers or an uncalibrated squeeze crimp will either under-crimp the barrel or split the nylon. No solder is required.