Scotchlok MV10-38R/SX 3M Ring Vinyl Insulated, 100/bottle, MV10-38R/SX

The MV10-38R/SX is sized for 12 to 10 AWG conductor. The yellow insulation is the color code for that range, so on a job where you're also running 22-16 AWG (red) or 16-14 AWG (blue) terminals, the yellow barrel is your visual check that the right terminal went on the right conductor. Maximum insulation outer diameter the funnel sleeve will accept is 0.250 inch, so heavily jacketed or double-insulated wire in that gauge may not seat.

Yes, the ring is drilled for a 3/8 inch stud. It is a standard-style ring tongue, meaning the closed ring goes over the stud and the nut clamps it down, so the connection can't back off the post the way a spade or flanged fork can. Overall tongue length is 1.26 inches with a 0.54 inch width, and the tongue stock is 0.04 inch thick.

Yes. The MV10-38R/SX carries a 600 V maximum recommended voltage rating for building wire, and 3M rates the vinyl insulation to 1000 V when used in signs, fixtures or luminaires. It is UL Listed under file E23438 and CSA Certified under LR22190.

Temperature range is -40 to 221 degrees F (-40 to 105 degrees C), which covers rooftop mechanical enclosures, unconditioned warehouse space, and cold storage. The barrel is electrolytic copper with tin plating for corrosion resistance, so it holds up better than bare copper in damp or coastal locations. The insulation itself is vinyl, not nylon or heat-shrink, so it is not a sealed connection against standing water.

A brazed seam means the rolled barrel is joined rather than left as a butt seam, so it won't split open under crimp pressure or pull apart when the conductor is loaded. Paired with the funnel-designed PVC sleeve, the strands feed in without birdcaging on the way to the stop. That matters most on 10 AWG stranded, which is stiff enough to peel back a plain butt-seam barrel during insertion.

RoHS 2011/65/EU compliant without exemption, and UL Listed plus CSA Certified for North American work. For federal or state contracts needing country of origin representation, 3M requires that certification come from 3M Trade Compliance rather than from the packaging.

Use the ring where the connection is safety or code critical and you don't want it walking off the stud. The MV10-38R/SX is a closed ring sized to 3/8 inch, so the nut has to come fully off before the wire can leave the post. A fork or spade terminal slides out under a loosened nut, which is why it gets used where terminals are swapped often and vibration is low. For motor leads, disconnect lugs, grounding bars and equipment studs that see vibration or thermal cycling, the ring is the one to specify.

They ship 50 per bottle. The bottle packaging is worth noting for a service van or a cart, since the terminals stay contained instead of scattering loose in a bin, and the yellow color code makes the 12-10 AWG bottle easy to pick out from the rest of the kit.