Sta-Kon RCS10-10FLX HEATSHR LKG FORK TERM, 12-10, No10,

The RCS10-10FLX takes 12 to 10 AWG conductor. That's the yellow color code on Sta-Kon insulated terminals, so if your crimp die set is color-coded, use the yellow die station. Anything smaller than 12 AWG will not hold in this barrel; step down to the blue (16-14 AWG) or red (22-16 AWG) size instead.

It's sized for a No. 10 stud or screw. The fork slot slides over a #10 terminal block screw without fully removing it, which is why fork tongues get used on control panels and terminal strips where you're landing wire on screws you don't want to back all the way out.

The heat shrink sleeve is applied after crimping. You hit it with a heat gun and it shrinks down over the crimp barrel and onto the wire jacket, sealing the joint against moisture and taking strain off the conductor where it exits the barrel. That makes it the right choice for outdoor panels, marine and wash-down areas, and anywhere vibration would work a plain vinyl-insulated terminal loose. A standard nylon or vinyl terminal is fine for a dry indoor enclosure and is faster to install since there's no heat step.

Yes, the RCS10-10FLX carries a 600 V rating, which covers normal commercial branch circuits, control wiring and motor circuits up to 600 volts.

A locking fork has turned-up or barbed tips on the tongue that catch under the screw head, so the terminal won't slide back out sideways if the screw loosens. A plain flanged spade just relies on screw pressure. On equipment that vibrates, or on a terminal strip you service often, the locking style is the safer pick. A ring terminal is more secure still, but you have to pull the screw completely out to install it.

The barrel is copper, so it's intended for copper conductor. Don't use it to terminate aluminum wire, that needs a terminal specifically listed AL/CU with the right inhibitor compound.

Use a crimper matched to insulated terminals in the 12-10 AWG range, not a bare-terminal nest, so the die closes on the barrel without cutting the sleeve. You'll also need a heat gun to recover the shrink after the crimp. Neither tool is supplied with the terminal.

Country of origin is the United States. That matters if you're on a government, federal or institutional job with domestic-sourcing language in the spec.